Complex high-pressure polymorphism of barium tungstate

We have studied BaWO 4 under compression at room temperature by means of x-ray diffraction and Raman spectroscopy. When compressed with neon as a pressure-transmitting medium (quasihydrostatic conditions), we found that BaWO 4 transforms from its low-pressure tetragonal structure into a much denser monoclinic structure. This result confirms our previous theoretical prediction based on ab initio calculations that the scheelite to BaWO 4-II transition occurs at room temperature if kinetic barriers are suppressed by pressure. However, our experiment without any pressure- transmitting medium has resulted in a phase transition to a completely different structure, suggesting nonhydrostaticity may be responsible for previously reported rich polymorphism in BaWO 4. The crystal structure of the low- and high-pressure phases from the quasihydrostatic experiments has been Rietveld refined. Additionally, for the tetragonal phase the effects of pressure on the unit-cell volume and lattice parameters are discussed. Finally, the pressure evolution of the Raman modes of different phases is reported and compared with previous studies. © 2012 American Physical Society.This research was supported by Spanish MEC (Grant No. MAT2010-21270-C04-01/04), MALTA Consolider Ingenio 2010 (Grant No. CSD2007-00045), and Vicerrectorado de Investigacion y Desarrollo of the Universitat Politecnica de Valencia (Grants No. UPV2011-0914 PAID-05-11 and No. UPV2011-0966 PAID-06-11). XRD data were collected at HPCAT, Advanced Photon Source (APS), Argonne National Laboratory. HPCAT is supported by CIW, CDAC, UNLV, and LLNL through funding from DOE-NNSA, DOE-BES, and NSF. APS is supported by DOE-BES under Contract No. DEAC02-06CH11357.Gomis Hilario, O.; Sans, JA.; Lacomba-Perales, R.; Errandonea, D.; Meng, Y.; Chervin, JC.; Polian, A. (2012). Complex high-pressure polymorphism of barium tungstate. Physical Review B. 86:54121-1-54121-10. https://doi.org/10.1103/PhysRevB.86.054121S54121-154121-1086Gürmen, E., Daniels, E., & King, J. S. (1971). Crystal Structure Refinement of SrMoO4, SrWO4, CaMoO4, and BaWO4 by Neutron Diffraction. The Journal of Chemical Physics, 55(3), 1093-1097. doi:10.1063/1.1676191Errandonea, D., & Manjón, F. J. (2008). Pressure effects on the structural and electronic properties of ABX4 scintillating crystals. Progress in Materials Science, 53(4), 711-773. doi:10.1016/j.pmatsci.2008.02.001Tan, D., Xiao, W., Zhou, W., Chen, M., Zhou, W., Li, X., … Liu, J. (2012). High pressure X-ray diffraction study on BaWO4-II. High Pressure Research, 1-8. doi:10.1080/08957959.2012.658789Lacomba-Perales, R., Errandonea, D., Segura, A., Ruiz-Fuertes, J., Rodríguez-Hernández, P., Radescu, S., … Muñoz, A. (2011). A combined high-pressure experimental and theoretical study of the electronic band-structure of scheelite-type AWO4 (A = Ca, Sr, Ba, Pb) compounds. Journal of Applied Physics, 110(4), 043703. doi:10.1063/1.3622322Lacomba-Perales, R., Martinez-García, D., Errandonea, D., Le Godec, Y., Philippe, J., Le Marchand, G., … López-Solano, J. (2010). Experimental and theoretical investigation of the stability of the monoclinicBaWO4-II phase at high pressure and high temperature. Physical Review B, 81(14). doi:10.1103/physrevb.81.144117Da-Yong, T., Wan-Sheng, X., Wen-Ge, Z., Mao-Shuang, S., Xiao-Lin, X., & Ming, C. (2009). Raman Investigation of BaWO4-II Phase under Hydrostatic Pressures up to 14.8 GPa. Chinese Physics Letters, 26(4), 046301. doi:10.1088/0256-307x/26/4/046301Manjón, F. J., Errandonea, D., Garro, N., Pellicer-Porres, J., Rodríguez-Hernández, P., Radescu, S., … Muñoz, A. (2006). Lattice dynamics study of scheelite tungstates under high pressure I.BaWO4. Physical Review B, 74(14). doi:10.1103/physrevb.74.144111Grzechnik, A., Crichton, W. A., Marshall, W. G., & Friese, K. (2006). High-pressure x-ray and neutron powder diffraction study of PbWO4and BaWO4scheelites. Journal of Physics: Condensed Matter, 18(11), 3017-3029. doi:10.1088/0953-8984/18/11/008Errandonea, D., Pellicer-Porres, J., Manjón, F. J., Segura, A., Ferrer-Roca, C., Kumar, R. S., … Aquilanti, G. (2006). Determination of the high-pressure crystal structure ofBaWO4andPbWO4. Physical Review B, 73(22). doi:10.1103/physrevb.73.224103Panchal, V., Garg, N., Chauhan, A. K., Sangeeta, & Sharma, S. M. (2004). High pressure phase transitions in BaWO4. Solid State Communications, 130(3-4), 203-208. doi:10.1016/j.ssc.2004.01.043Jayaraman, A., Batlogg, B., & VanUitert, L. G. (1983). High-pressure Raman study of alkaline-earth tungstates and a new pressure-induced phase transition in BaWO4. Physical Review B, 28(8), 4774-4777. doi:10.1103/physrevb.28.4774Kawada, I., Kato, K., & Fujita, T. (1974). BaWO4-II (a high-pressure form). Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 30(8), 2069-2071. doi:10.1107/s0567740874006431Fujita, T., Yamaoka, S., & Fukunaga, O. (1974). Pressure induced phase transformation in BaWO4. Materials Research Bulletin, 9(2), 141-146. doi:10.1016/0025-5408(74)90193-7Manjon, F. J., Errandonea, D., Garro, N., Pellicer-Porres, J., López-Solano, J., Rodríguez-Hernández, P., … Muñoz, A. (2006). Lattice dynamics study of scheelite tungstates under high pressure II.PbWO4. Physical Review B, 74(14). doi:10.1103/physrevb.74.144112Errandonea, D., Martínez-García, D., Lacomba-Perales, R., Ruiz-Fuertes, J., & Segura, A. (2006). Effects of high pressure on the optical absorption spectrum of scintillating PbWO4 crystals. Applied Physics Letters, 89(9), 091913. doi:10.1063/1.2345228Mao, H. K., Xu, J., & Bell, P. M. (1986). Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions. Journal of Geophysical Research, 91(B5), 4673. doi:10.1029/jb091ib05p04673Klotz, S., Chervin, J.-C., Munsch, P., & Le Marchand, G. (2009). Hydrostatic limits of 11 pressure transmitting media. Journal of Physics D: Applied Physics, 42(7), 075413. doi:10.1088/0022-3727/42/7/075413Hammersley, A. P., Svensson, S. O., Hanfland, M., Fitch, A. N., & Hausermann, D. (1996). Two-dimensional detector software: From real detector to idealised image or two-theta scan. High Pressure Research, 14(4-6), 235-248. doi:10.1080/08957959608201408Holland, T. J. B., & Redfern, S. A. T. (1997). Unit cell refinement from powder diffraction data: the use of regression diagnostics. Mineralogical Magazine, 61(404), 65-77. doi:10.1180/minmag.1997.061.404.07Toby, B. H. (2001). EXPGUI, a graphical user interface forGSAS. Journal of Applied Crystallography, 34(2), 210-213. doi:10.1107/s0021889801002242Kraus, W., & Nolze, G. (1996). POWDER CELL – a program for the representation and manipulation of crystal structures and calculation of the resulting X-ray powder patterns. Journal of Applied Crystallography, 29(3), 301-303. doi:10.1107/s0021889895014920Birch, F. (1978). Finite strain isotherm and velocities for single-crystal and polycrystalline NaCl at high pressures and 300°K. Journal of Geophysical Research, 83(B3), 1257. doi:10.1029/jb083ib03p01257Liu, H., Ding, Y., Somayazulu, M., Qian, J., Shu, J., Häusermann, D., & Mao, H. (2005). Rietveld refinement study of the pressure dependence of the internal structural parameteruin the wurtzite phase of ZnO. Physical Review B, 71(21). doi:10.1103/physrevb.71.212103Liu, H., Hu, J., Shu, J., Häusermann, D., & Mao, H. (2004). Lack of the critical pressure for weakening of size-induced stiffness in 3C–SiC nanocrystals under hydrostatic compression. Applied Physics Letters, 85(11), 1973-1975. doi:10.1063/1.1789240Ruiz-Fuertes, J., Errandonea, D., Lacomba-Perales, R., Segura, A., González, J., Rodríguez, F., … Tu, C. Y. (2010). High-pressure structural phase transitions inCuWO4. Physical Review B, 81(22). doi:10.1103/physrevb.81.224115Santamaría-Pérez, D., Gracia, L., Garbarino, G., Beltrán, A., Chuliá-Jordán, R., Gomis, O., … Segura, A. (2011). High-pressure study of the behavior of mineral barite by x-ray diffraction. Physical Review B, 84(5). doi:10.1103/physrevb.84.054102Finger, L. W., Kroeker, M., & Toby, B. H. (2007). DRAWxtl, an open-source computer program to produce crystal structure drawings. Journal of Applied Crystallography, 40(1), 188-192. doi:10.1107/s0021889806051557Achary, S. N., Patwe, S. J., Mathews, M. D., & Tyagi, A. K. (2006). High temperature crystal chemistry and thermal expansion of synthetic powellite (CaMoO4): A high temperature X-ray diffraction (HT-XRD) study. Journal of Physics and Chemistry of Solids, 67(4), 774-781. doi:10.1016/j.jpcs.2005.11.009Machon, D., Dmitriev, V. P., Bouvier, P., Timonin, P. N., Shirokov, V. B., & Weber, H.-P. (2003). Pseudoamorphization ofCs2HgBr4. Physical Review B, 68(14). doi:10.1103/physrevb.68.144104Ruiz-Fuertes, J., Friedrich, A., Pellicer-Porres, J., Errandonea, D., Segura, A., Morgenroth, W., … Polian, A. (2011). Structure Solution of the High-Pressure Phase of CuWO4and Evolution of the Jahn–Teller Distortion. Chemistry of Materials, 23(18), 4220-4226. doi:10.1021/cm201592hErrandonea, D., Meng, Y., Somayazulu, M., & Häusermann, D. (2005). Pressure-induced transition in titanium metal: a systematic study of the effects of uniaxial stress. Physica B: Condensed Matter, 355(1-4), 116-125. doi:10.1016/j.physb.2004.10.030Errandonea, D., Kumar, R. S., Ruiz-Fuertes, J., Segura, A., & Haussühl, E. (2011). High-pressure study of substrate material ScAlMgO4. Physical Review B, 83(14). doi:10.1103/physrevb.83.144104Wang, J.-T., Chen, C., & Kawazoe, Y. (2011). Low-Temperature Phase Transformation from Graphite tosp3Orthorhombic Carbon. Physical Review Letters, 106(7). doi:10.1103/physrevlett.106.075501Errandonea, D., & Manjón, F. J. (2009). On the ferroelastic nature of the scheelite-to-fergusonite phase transition in orthotungstates and orthomolybdates. Materials Research Bulletin, 44(4), 807-811. doi:10.1016/j.materresbull.2008.09.024Maczka, M., Souza Filho, A. G., Paraguassu, W., Freire, P. T. C., Mendes Filho, J., & Hanuza, J. (2012). Pressure-induced structural phase transitions and amorphization in selected molybdates and tungstates. Progress in Materials Science, 57(7), 1335-1381. doi:10.1016/j.pmatsci.2012.01.001Flórez, M., Contreras-García, J., Recio, J. M., & Marqués, M. (2009). Quantum-mechanical calculations of zircon to scheelite transition pathways inZrSiO4. Physical Review B, 79(10). doi:10.1103/physrevb.79.104101Errandonea, D., Gracia, L., Beltrán, A., Vegas, A., & Meng, Y. (2011). Pressure-induced phase transitions in AgClO4. Physical Review B, 84(6). doi:10.1103/physrevb.84.06410

Room-temperature vibrational properties of multiferroic MnWO4 under quasi-hydrostatic compression up to 39 GPa

The multiferroic manganese tungstate (MnWO4) has been studied by high-pressure Raman spectroscopy at room temperature under quasi-hydrostatic conditions up to 39.3 GPa. The low-pressure wolframite phase undergoes a phase transition at 25.7 GPa, a pressure around 8 GPa higher than that found in previous works, which used less hydrostatic pressure-transmitting media. The pressure dependence of the Raman active modes of both the low-and high-pressure phases is reported and discussed comparing with the results available in the literature for MnWO4 and related wolframites. A gradual pressure-induced phase transition from the low-to the high-pressure phase is suggested on the basis of the linear intensity decrease of the Raman mode with the lowest frequency up to the end of the phase transition. (C) 2014 AIP Publishing LLC.This work has been supported by the Spanish government under Grant No. MAT2010-21270-C04-01/04, by MALTA Consolider Ingenio 2010 Project (CSD2007-00045), by Generalitat Valenciana (GVA-ACOMP-2013-1012), and by the Vicerrectorado de Investigacion y Desarrollo of the Universidad Politecnica de Valencia (UPV2011-0914 PAID-05-11 and UPV2011-0966 PAID-06-11). We thank Professor Gospodinov, Institute of Scintillating Materials in Ukraine, for providing us high-quality MnWO4 single crystals. J.R.-F. thanks the Alexander von Humboldt Foundation for a postdoctoral fellowship. A. F. acknowledges support from the Germany Research foundation within the priority program SPP1236 (Project No. FR-2491/2-1). The use of the SPP1236 central facility in Frankfurt is acknowledged.Ruiz-Fuertes, J.; Errandonea, D.; Gomis Hilario, O.; Friedrich, A.; Manjón Herrera, FJ. (2014). Room-temperature vibrational properties of multiferroic MnWO4 under quasi-hydrostatic compression up to 39 GPa. Journal of Applied Physics. 115(4):43510-1-43510-5. https://doi.org/10.1063/1.4863236S43510-143510-51154Mikhailik, V. B., Kraus, H., Kapustyanyk, V., Panasyuk, M., Prots, Y., Tsybulskyi, V., & Vasylechko, L. (2008). Structure, luminescence and scintillation properties of the MgWO4–MgMoO4system. Journal of Physics: Condensed Matter, 20(36), 365219. doi:10.1088/0953-8984/20/36/365219Butler, M. A. (1977). Photoelectrolysis and physical properties of the semiconducting electrode WO2. Journal of Applied Physics, 48(5), 1914-1920. doi:10.1063/1.323948Traversa, E. (1995). Ceramic sensors for humidity detection: the state-of-the-art and future developments. Sensors and Actuators B: Chemical, 23(2-3), 135-156. doi:10.1016/0925-4005(94)01268-mTaniguchi, K., Abe, N., Takenobu, T., Iwasa, Y., & Arima, T. (2006). Ferroelectric Polarization Flop in a Frustrated MagnetMnWO4Induced by a Magnetic Field. Physical Review Letters, 97(9). doi:10.1103/physrevlett.97.097203Errandonea, D., Manjón, F. J., Garro, N., Rodríguez-Hernández, P., Radescu, S., Mujica, A., … Tu, C. Y. (2008). Combined Raman scattering andab initioinvestigation of pressure-induced structural phase transitions in the scintillatorZnWO4. Physical Review B, 78(5). doi:10.1103/physrevb.78.054116Ruiz-Fuertes, J., López-Moreno, S., López-Solano, J., Errandonea, D., Segura, A., Lacomba-Perales, R., … Tu, C. Y. (2012). Pressure effects on the electronic and optical properties ofAWO4wolframites (A =Cd, Mg, Mn, and Zn): The distinctive behavior of multiferroic MnWO4. Physical Review B, 86(12). doi:10.1103/physrevb.86.125202Sleight, A. W. (1972). Accurate cell dimensions for ABO4 molybdates and tungstates. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 28(10), 2899-2902. doi:10.1107/s0567740872007186Ruiz-Fuertes, J., López-Moreno, S., Errandonea, D., Pellicer-Porres, J., Lacomba-Perales, R., Segura, A., … González, J. (2010). High-pressure phase transitions and compressibility of wolframite-type tungstates. Journal of Applied Physics, 107(8), 083506. doi:10.1063/1.3380848Ruiz-Fuertes, J., Errandonea, D., López-Moreno, S., González, J., Gomis, O., Vilaplana, R., … Nagornaya, L. L. (2011). High-pressure Raman spectroscopy and lattice-dynamics calculations on scintillating MgWO4: Comparison with isomorphic compounds. Physical Review B, 83(21). doi:10.1103/physrevb.83.214112Dai, R. C., Ding, X., Wang, Z. P., & Zhang, Z. M. (2013). Pressure and temperature dependence of Raman scattering of MnWO4. Chemical Physics Letters, 586, 76-80. doi:10.1016/j.cplett.2013.09.035Macavei, J., & Schulz, H. (1993). The crystal structure of wolframite type tungstates at high pressure. Zeitschrift für Kristallographie - Crystalline Materials, 207(2). doi:10.1524/zkri.1993.207.part-2.193Chaudhury, R. P., Yen, F., dela Cruz, C. R., Lorenz, B., Wang, Y. Q., Sun, Y. Y., & Chu, C. W. (2008). Thermal expansion and pressure effect in. Physica B: Condensed Matter, 403(5-9), 1428-1430. doi:10.1016/j.physb.2007.10.327Klotz, S., Chervin, J.-C., Munsch, P., & Le Marchand, G. (2009). Hydrostatic limits of 11 pressure transmitting media. Journal of Physics D: Applied Physics, 42(7), 075413. doi:10.1088/0022-3727/42/7/075413Iliev, M. N., Gospodinov, M. M., & Litvinchuk, A. P. (2009). Raman spectroscopy ofMnWO4. Physical Review B, 80(21). doi:10.1103/physrevb.80.212302Mao, H. K., Xu, J., & Bell, P. M. (1986). Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions. Journal of Geophysical Research, 91(B5), 4673. doi:10.1029/jb091ib05p04673Mączka, M., Ptak, M., Pereira da Silva, K., Freire, P. T. C., & Hanuza, J. (2012). High-pressure Raman scattering and an anharmonicity study of multiferroic wolframite-type Mn0.97Fe0.03WO4. Journal of Physics: Condensed Matter, 24(34), 345403. doi:10.1088/0953-8984/24/34/345403Errandonea, D., Gracia, L., Lacomba-Perales, R., Polian, A., & Chervin, J. C. (2013). Compression of scheelite-type SrMoO4 under quasi-hydrostatic conditions: Redefining the high-pressure structural sequence. Journal of Applied Physics, 113(12), 123510. doi:10.1063/1.4798374Gomis, O., Sans, J. A., Lacomba-Perales, R., Errandonea, D., Meng, Y., Chervin, J. C., & Polian, A. (2012). Complex high-pressure polymorphism of barium tungstate. Physical Review B, 86(5). doi:10.1103/physrevb.86.054121Li, H., Zhou, S., & Zhang, S. (2007). The relationship between the thermal expansions and structures of ABO4 oxides. Journal of Solid State Chemistry, 180(2), 589-595. doi:10.1016/j.jssc.2006.11.023N. W. Ashkroft and N. D. Mermin, Solid State Physics (W. B. Saunders Company, Philadelphia, 1976), Chap. 25, p. 493.Hofmeister, A. M., & Mao, H. -k. (2002). Redefinition of the mode Gruneisen parameter for polyatomic substances and thermodynamic implications. Proceedings of the National Academy of Sciences, 99(2), 559-564. doi:10.1073/pnas.241631698Lacomba-Perales, R., Martínez-García, D., Errandonea, D., Le Godec, Y., Philippe, J., & Morard, G. (2009). High-pressure and high-temperature X-ray diffraction studies of scheelite BaWO4. High Pressure Research, 29(1), 76-82. doi:10.1080/0895795080241779

Lattice dynamics of Sb2Te3 at high pressures

We report an experimental and theoretical lattice dynamics study of antimony telluride (Sb 2Te 3) up to 26 GPa together with a theoretical study of its structural stability under pressure. Raman-active modes of the low-pressure rhombohedral (R-3m) phase were observed up to 7.7 GPa. Changes of the frequencies and linewidths were observed around 3.5 GPa where an electronic topological transition was previously found. Raman-mode changes evidence phase transitions at 7.7, 14.5, and 25GPa. The frequencies and pressure coefficients of the new phases above 7.7 and 14.5 GPa agree with those calculated for the monoclinic C2/m and C2/c structures recently observed at high pressures in Bi 2Te 3 and also for the C2/m phase in the case of Bi 2Se 3 and Sb 2Te 3. Above 25 GPa no Raman-active modes are observed in Sb 2Te 3, similarly to the case of Bi 2Te 3 and Bi 2Se 3. Therefore, it is possible that the structure of Sb 2Te 3 above 25 GPa is the same disordered bcc phase already found in Bi 2Te 3 by x-ray diffraction studies. Upon pressure release, Sb 2Te 3 reverts back to the original rhombohedral phase after considerable hysteresis. Raman- and IR-mode symmetries, frequencies, and pressure coefficients in the different phases are reported and discussed. © 2011 American Physical Society.This work has been done under financial support from Spanish MICINN under Project Nos. MAT2010-21270-C04-03/04 and CSD-2007-00045 and supported by the Ministry of Education, Youth and Sports of the Czech Republic (MSM 0021627501). E. P.-G. acknowledges the financial support of the Spanish MEC under a FPI fellowship. Supercomputer time has been provided by the Red Espanola de Supercomputacion (RES) and the MALTA cluster.Gomis Hilario, O.; Vilaplana Cerda, RI.; Manjón Herrera, FJ.; Rodríguez-Hernández, P.; Pérez-González, E.; Muñoz, A.; Kucek, V.... (2011). Lattice dynamics of Sb2Te3 at high pressures. Physical Review B. 84:174305-1-174305-12. https://doi.org/10.1103/PhysRevB.84.174305S174305-1174305-1284Snyder, G. J., & Toberer, E. S. (2008). Complex thermoelectric materials. Nature Materials, 7(2), 105-114. doi:10.1038/nmat2090Venkatasubramanian, R., Siivola, E., Colpitts, T., & O’Quinn, B. (2001). Thin-film thermoelectric devices with high room-temperature figures of merit. Nature, 413(6856), 597-602. doi:10.1038/35098012Harman, T. C. (2002). Quantum Dot Superlattice Thermoelectric Materials and Devices. Science, 297(5590), 2229-2232. doi:10.1126/science.1072886Chen, J., Sun, T., Sim, D., Peng, H., Wang, H., Fan, S., … Yan, Q. (2010). Sb2Te3Nanoparticles with Enhanced Seebeck Coefficient and Low Thermal Conductivity. Chemistry of Materials, 22(10), 3086-3092. doi:10.1021/cm9038297Yin, Y., Sone, H., & Hosaka, S. (2007). Characterization of nitrogen-doped Sb2Te3 films and their application to phase-change memory. Journal of Applied Physics, 102(6), 064503. doi:10.1063/1.2778737Kim, M. S., Cho, S. H., Hong, S. K., Roh, J. S., & Choi, D. J. (2008). Crystallization characteristics of nitrogen-doped Sb2Te3 films for PRAM application. Ceramics International, 34(4), 1043-1046. doi:10.1016/j.ceramint.2007.09.078Anderson, T. L., & Krause, H. B. (1974). Refinement of the Sb2Te3 and Sb2Te2Se structures and their relationship to nonstoichiometric Sb2Te3−y Se y compounds. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 30(5), 1307-1310. doi:10.1107/s0567740874004729Zhang, H., Liu, C.-X., Qi, X.-L., Dai, X., Fang, Z., & Zhang, S.-C. (2009). Topological insulators in Bi2Se3, Bi2Te3 and Sb2Te3 with a single Dirac cone on the surface. Nature Physics, 5(6), 438-442. doi:10.1038/nphys1270Hasan, M. Z., & Kane, C. L. (2010). Colloquium: Topological insulators. Reviews of Modern Physics, 82(4), 3045-3067. doi:10.1103/revmodphys.82.3045Moore, J. E. (2010). The birth of topological insulators. Nature, 464(7286), 194-198. doi:10.1038/nature08916Xia, Y., Qian, D., Hsieh, D., Wray, L., Pal, A., Lin, H., … Hasan, M. Z. (2009). Observation of a large-gap topological-insulator class with a single Dirac cone on the surface. Nature Physics, 5(6), 398-402. doi:10.1038/nphys1274Wang, G., & Cagin, T. (2007). Electronic structure of the thermoelectric materialsBi2Te3andSb2Te3from first-principles calculations. Physical Review B, 76(7). doi:10.1103/physrevb.76.075201Chen, Y. L., Analytis, J. G., Chu, J.-H., Liu, Z. K., Mo, S.-K., Qi, X. L., … Shen, Z.-X. (2009). Experimental Realization of a Three-Dimensional Topological Insulator, Bi2Te3. Science, 325(5937), 178-181. doi:10.1126/science.1173034Badding, J. V., Meng, J. F., & Polvani, D. A. (1998). Pressure Tuning in the Search for New and Improved Solid State Materials. Chemistry of Materials, 10(10), 2889-2894. doi:10.1021/cm9802393Polvani, D. A., Meng, J. F., Chandra Shekar, N. V., Sharp, J., & Badding, J. V. (2001). Large Improvement in Thermoelectric Properties in Pressure-Tuned p-Type Sb1.5Bi0.5Te3. Chemistry of Materials, 13(6), 2068-2071. doi:10.1021/cm000888qChandra Shekar, N. V., Polvani, D. A., Meng, J. F., & Badding, J. V. (2005). Improved thermoelectric properties due to electronic topological transition under high pressure. Physica B: Condensed Matter, 358(1-4), 14-18. doi:10.1016/j.physb.2004.12.020Ovsyannikov, S. V., Shchennikov, V. V., Vorontsov, G. V., Manakov, A. Y., Likhacheva, A. Y., & Kulbachinskii, V. A. (2008). Giant improvement of thermoelectric power factor of Bi2Te3 under pressure. Journal of Applied Physics, 104(5), 053713. doi:10.1063/1.2973201Ovsyannikov, S. V., & Shchennikov, V. V. (2010). High-Pressure Routes in the Thermoelectricity or How One Can Improve a Performance of Thermoelectrics†. Chemistry of Materials, 22(3), 635-647. doi:10.1021/cm902000xLi, C., Ruoff, A. L., & Spencer, C. W. (1961). Effect of Pressure on the Energy Gap of Bi2Te3. Journal of Applied Physics, 32(9), 1733-1735. doi:10.1063/1.1728426Khvostantsev, L. G., Orlov, A. I., Abrikosov, N. K., & Ivanova, L. D. (1980). Thermoelectric properties and phase transition in Sb2Te3 under hydrostatic pressure up to 9 GPa. Physica Status Solidi (a), 58(1), 37-40. doi:10.1002/pssa.2210580103Sakai, N., Kajiwara, T., Takemura, K., Minomura, S., & Fujii, Y. (1981). Pressure-induced phase transition in Sb2Te3. Solid State Communications, 40(12), 1045-1047. doi:10.1016/0038-1098(81)90248-9Khvostantsev, L. G., Orlov, A. I., Abrikosov, N. K., & Ivanova, L. D. (1985). Kinetic Properties and Phase Transitions in Sb2Te3 under Hydrostatic Pressure up to 9 GPa. physica status solidi (a), 89(1), 301-309. doi:10.1002/pssa.2210890132Thonhauser, T., Scheidemantel, T. J., Sofo, J. O., Badding, J. V., & Mahan, G. D. (2003). Thermoelectric properties ofSb2Te3under pressure and uniaxial stress. Physical Review B, 68(8). doi:10.1103/physrevb.68.085201Thonhauser, T. (2004). Influence of negative pressure on thermoelectric properties of Sb2Te3. Solid State Communications, 129(4), 249-253. doi:10.1016/j.ssc.2003.10.006Einaga, M., Tanabe, Y., Nakayama, A., Ohmura, A., Ishikawa, F., & Yamada, Y. (2010). New superconducting phase of Bi2Te3under pressure above 11 GPa. Journal of Physics: Conference Series, 215, 012036. doi:10.1088/1742-6596/215/1/012036Zhang, J. L., Zhang, S. J., Weng, H. M., Zhang, W., Yang, L. X., Liu, Q. Q., … Jin, C. Q. (2010). Pressure-induced superconductivity in topological parent compound Bi2Te3. Proceedings of the National Academy of Sciences, 108(1), 24-28. doi:10.1073/pnas.1014085108Jacobsen, M. K., Kumar, R. S., Cornelius, A. L., Sinogeiken, S. V., Nico, M. F., Elert, M., … Nguyen, J. (2008). HIGH PRESSURE X-RAY DIFFRACTION STUDIES OF Bi[sub 2−x]Sb[sub x]Te[sub 3] (x = 0,1,2). doi:10.1063/1.2833001Nakayama, A., Einaga, M., Tanabe, Y., Nakano, S., Ishikawa, F., & Yamada, Y. (2009). Structural phase transition in Bi2Te3 under high pressure. High Pressure Research, 29(2), 245-249. doi:10.1080/08957950902951633Einaga, M., Ohmura, A., Nakayama, A., Ishikawa, F., Yamada, Y., & Nakano, S. (2011). Pressure-induced phase transition of Bi2Te3to a bcc structure. Physical Review B, 83(9). doi:10.1103/physrevb.83.092102Zhu, L., Wang, H., Wang, Y., Lv, J., Ma, Y., Cui, Q., … Zou, G. (2011). Substitutional Alloy of Bi and Te at High Pressure. Physical Review Letters, 106(14). doi:10.1103/physrevlett.106.145501Itskevich, E. S., Kashirskaya, L. M., & Kraidenov, V. F. (1997). Anomalies in the low-temperature thermoelectric power of p-Bi2Te3 and Te associated with topological electronic transitions under pressure. Semiconductors, 31(3), 276-278. doi:10.1134/1.1187126Polian, A., Gauthier, M., Souza, S. M., Trichês, D. M., Cardoso de Lima, J., & Grandi, T. A. (2011). Two-dimensional pressure-induced electronic topological transition in Bi2Te3. Physical Review B, 83(11). doi:10.1103/physrevb.83.113106Vilaplana, R., Santamaría-Pérez, D., Gomis, O., Manjón, F. J., González, J., Segura, A., … Kucek, V. (2011). Structural and vibrational study of Bi2Se3under high pressure. Physical Review B, 84(18). doi:10.1103/physrevb.84.184110Richter, W., & Becker, C. R. (1977). A Raman and far-infrared investigation of phonons in the rhombohedral V2–VI3 compounds Bi2Te3, Bi2Se3, Sb2Te3 and Bi2(Te1−xSex)3 (0 <x < 1), (Bi1−ySby)2Te3 (0 <y < 1). Physica Status Solidi (b), 84(2), 619-628. doi:10.1002/pssb.2220840226Sosso, G. C., Caravati, S., & Bernasconi, M. (2009). Vibrational properties of crystalline Sb2Te3from first principles. Journal of Physics: Condensed Matter, 21(9), 095410. doi:10.1088/0953-8984/21/9/095410Dagens, L. (1978). Phonon anomaly near a Fermi surface topological transition. Journal of Physics F: Metal Physics, 8(10), 2093-2113. doi:10.1088/0305-4608/8/10/010Dagens, L., & Lopez-Rios, C. (1979). Thermodynamic properties of a metal near a Fermi surface topological transition: the anomalous electron-phonon interaction contribution. Journal of Physics F: Metal Physics, 9(11), 2195-2216. doi:10.1088/0305-4608/9/11/011Goncharov, A. ., & Struzhkin, V. . (2003). Pressure dependence of the Raman spectrum, lattice parameters and superconducting critical temperature of MgB2: evidence for pressure-driven phonon-assisted electronic topological transition. Physica C: Superconductivity, 385(1-2), 117-130. doi:10.1016/s0921-4534(02)02311-0Antonangeli, D., Farber, D. L., Said, A. H., Benedetti, L. R., Aracne, C. M., Landa, A., … Klepeis, J. E. (2010). Shear softening in tantalum at megabar pressures. Physical Review B, 82(13). doi:10.1103/physrevb.82.132101Santamaría-Pérez, D., Vegas, A., Muehle, C., & Jansen, M. (2011). Structural behaviour of alkaline sulfides under compression: High-pressure experimental study on Cs2S. The Journal of Chemical Physics, 135(5), 054511. doi:10.1063/1.3617236Vilaplana, R., Gomis, O., Manjón, F. J., Segura, A., Pérez-González, E., Rodríguez-Hernández, P., … Kucek, V. (2011). High-pressure vibrational and optical study of Bi2Te3. Physical Review B, 84(10). doi:10.1103/physrevb.84.104112Larson, P. (2006). Effects of uniaxial and hydrostatic pressure on the valence band maximum inSb2Te3: An electronic structure study. Physical Review B, 74(20). doi:10.1103/physrevb.74.205113Lošťák, P., Beneš, L., Civiš, S., & Süssmann, H. (1990). Preparation and some physical properties of Bi2−xInxSe3 single crystals. Journal of Materials Science, 25(1), 277-282. doi:10.1007/bf00544220Horák, J., Quayle, P. C., Dyck, J. S., Drašar, Č., Lošt’ák, P., & Uher, C. (2008). Defect structure of Sb2−xCrxTe3 single crystals. Journal of Applied Physics, 103(1), 013516. doi:10.1063/1.2826940Piermarini, G. J., Block, S., & Barnett, J. D. (1973). Hydrostatic limits in liquids and solids to 100 kbar. Journal of Applied Physics, 44(12), 5377-5382. doi:10.1063/1.1662159Errandonea, D., Meng, Y., Somayazulu, M., & Häusermann, D. (2005). Pressure-induced transition in titanium metal: a systematic study of the effects of uniaxial stress. Physica B: Condensed Matter, 355(1-4), 116-125. doi:10.1016/j.physb.2004.10.030Syassen, K. (2008). Ruby under pressure. High Pressure Research, 28(2), 75-126. doi:10.1080/08957950802235640Hohenberg, P., & Kohn, W. (1964). Inhomogeneous Electron Gas. Physical Review, 136(3B), B864-B871. doi:10.1103/physrev.136.b864Kresse, G., & Hafner, J. (1993). Ab initiomolecular dynamics for liquid metals. Physical Review B, 47(1), 558-561. doi:10.1103/physrevb.47.558Kresse, G., & Hafner, J. (1994). Ab initiomolecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium. Physical Review B, 49(20), 14251-14269. doi:10.1103/physrevb.49.14251Kresse, G., & Furthmüller, J. (1996). Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Computational Materials Science, 6(1), 15-50. doi:10.1016/0927-0256(96)00008-0Kresse, G., & Furthmüller, J. (1996). Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set. Physical Review B, 54(16), 11169-11186. doi:10.1103/physrevb.54.11169Blöchl, P. E. (1994). Projector augmented-wave method. Physical Review B, 50(24), 17953-17979. doi:10.1103/physrevb.50.17953Kresse, G., & Joubert, D. (1999). From ultrasoft pseudopotentials to the projector augmented-wave method. Physical Review B, 59(3), 1758-1775. doi:10.1103/physrevb.59.1758Perdew, J. P., Ruzsinszky, A., Csonka, G. I., Vydrov, O. A., Scuseria, G. E., Constantin, L. A., … Burke, K. (2008). Restoring the Density-Gradient Expansion for Exchange in Solids and Surfaces. Physical Review Letters, 100(13). doi:10.1103/physrevlett.100.136406Mujica, A., Rubio, A., Muñoz, A., & Needs, R. J. (2003). High-pressure phases of group-IV, III–V, and II–VI compounds. Reviews of Modern Physics, 75(3), 863-912. doi:10.1103/revmodphys.75.863Blanco, M. A., Francisco, E., & Luaña, V. (2004). GIBBS: isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model. Computer Physics Communications, 158(1), 57-72. doi:10.1016/j.comphy.2003.12.001Cardona, M. (2004). Phonon widths versus pressure. High Pressure Research, 24(1), 17-23. doi:10.1080/08957950310001635819Cardona, M. (2004). Effects of pressure on the phonon–phonon and electron–phonon interactions in semiconductors. physica status solidi (b), 241(14), 3128-3137. doi:10.1002/pssb.200405202Ulrich, C., Mroginski, M. A., Goñi, A. R., Cantarero, A., Schwarz, U., Muñoz, V., & Syassen, K. (1996). Vibrational Properties of InSe under Pressure: Experiment and Theory. physica status solidi (b), 198(1), 121-127. doi:10.1002/pssb.2221980117Kulibekov, A. M., Olijnyk, H. P., Jephcoat, A. P., Salaeva, Z. Y., Onari, S., & Allakhverdiev, K. R. (2003). Raman scattering under pressure and the phase transition in ɛ-GaSe. physica status solidi (b), 235(2), 517-520. doi:10.1002/pssb.200301613Cheng, W., & Ren, S.-F. (2011). Phonons of single quintuple Bi2Te3and Bi2Se3films and bulk materials. Physical Review B, 83(9). doi:10.1103/physrevb.83.094301Buga, S. G., Serebryanaya, N. R., Dubitskiy, G. A., Semenova, E. E., Aksenenkov, V. V., & Blank, V. D. (2011). Structure and electrical properties of Sb2Te3and Bi0.4Sb1.6Te3metastable phases obtained by HPHT treatment. High Pressure Research, 31(1), 86-90. doi:10.1080/08957959.2010.52342

Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System

Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc.) of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone) after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.This research has been supported by the European COST Action CM0805: The Chemical Cosmos.Boduch, P.; Da Silveira, EF.; Domaracka, A.; Gomis Hilario, O.; Lv, XY.; Palumbo, ME.; Pilling, S.... (2011). Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System. Advances in Astronomy. 1-10. doi:10.1155/2011/327641S11

High-pressure theoretical and experimental study of HgWO4

This is an Author's Accepted Manuscript of an article published in Lopez-Solano, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Santamaria-Perez, D. et al.(2011). High-pressure theoretical and experimental study of HgWO4. High Pressure Research. 31(1):58-63. doi:10.1080/08957959.2010.521735HgWO 4 at ambient pressure is characterized using a combination of ab initio calculations, X-ray diffraction and Raman scattering measurements. The effect of low pressure and temperature on the structural stability is analysed. Extending our ab initio study to the range of higher pressures, a sequence of stable phases up to 30GPa is proposed. © 2011 Taylor & Francis.We thank J.M. Menendez for his help in the use of the GIBBS code. This work has been supported by the Spanish MEC under Projects MAT2007-65990-C03-01/03, MAT2010-21270-C04-03/04 and CSD-2007-00045 and by the "Vicerrectorado de Innovacion y Desarrollo de la UPV" (PAID-05-2009 through project UPV2010-0096). We gratefully acknowledge computational time provided by the "Red Espanola de Supercomputacion" at the supercomputer "Atlante". S. R. acknowledges financial support from the "Vicerrectorado de Investigacion de la UPV" through grant PAID-02-09-3085.Lopez-Solano, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Santamaria-Perez, D.; Manjón Herrera, FJ.; Ray, S.; Gomis Hilario, O.... (2011). High-pressure theoretical and experimental study of HgWO4. High Pressure Research. 31(1):58-63. https://doi.org/10.1080/08957959.2010.521735S5863311Manjón, F. J., & Errandonea, D. (2009). Pressure-induced structural phase transitions in materials and earth sciences. physica status solidi (b), 246(1), 9-31. doi:10.1002/pssb.200844238Errandonea, D., Manjón, F. J., Garro, N., Rodríguez-Hernández, P., Radescu, S., Mujica, A., … Tu, C. Y. (2008). Combined Raman scattering andab initioinvestigation of pressure-induced structural phase transitions in the scintillatorZnWO4. Physical Review B, 78(5). doi:10.1103/physrevb.78.054116Ruiz-Fuertes, J., López-Moreno, S., Errandonea, D., Pellicer-Porres, J., Lacomba-Perales, R., Segura, A., … González, J. (2010). High-pressure phase transitions and compressibility of wolframite-type tungstates. Journal of Applied Physics, 107(8), 083506. doi:10.1063/1.3380848Lacomba-Perales, R., Errandonea, D., Martinez-Garcia, D., Rodríguez-Hernández, P., Radescu, S., Mujica, A., … Polian, A. (2009). Phase transitions in wolframite-typeCdWO4at high pressure studied by Raman spectroscopy and density-functional theory. Physical Review B, 79(9). doi:10.1103/physrevb.79.094105Manjón, F. J., López-Solano, J., Ray, S., Gomis, O., Santamaría-Pérez, D., Mollar, M., … Muñoz, A. (2010). High-pressure structural and lattice dynamical study ofHgWO4. Physical Review B, 82(3). doi:10.1103/physrevb.82.035212Kresse, G., & Hafner, J. (1993). Ab initiomolecular dynamics for liquid metals. Physical Review B, 47(1), 558-561. doi:10.1103/physrevb.47.558Kresse, G., & Furthmüller, J. (1996). Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set. Physical Review B, 54(16), 11169-11186. doi:10.1103/physrevb.54.11169Blöchl, P. E. (1994). Projector augmented-wave method. Physical Review B, 50(24), 17953-17979. doi:10.1103/physrevb.50.17953Perdew, J. P., Ruzsinszky, A., Csonka, G. I., Vydrov, O. A., Scuseria, G. E., Constantin, L. A., … Burke, K. (2008). Restoring the Density-Gradient Expansion for Exchange in Solids and Surfaces. Physical Review Letters, 100(13). doi:10.1103/physrevlett.100.136406Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13(12), 5188-5192. doi:10.1103/physrevb.13.5188Blanco, M. A., Francisco, E., & Luaña, V. (2004). GIBBS: isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model. Computer Physics Communications, 158(1), 57-72. doi:10.1016/j.comphy.2003.12.001Kresse, G., Furthmüller, J., & Hafner, J. (1995). Ab initioForce Constant Approach to Phonon Dispersion Relations of Diamond and Graphite. Europhysics Letters (EPL), 32(9), 729-734. doi:10.1209/0295-5075/32/9/005Wahl, R., Vogtenhuber, D., & Kresse, G. (2008). SrTiO3andBaTiO3revisited using the projector augmented wave method: Performance of hybrid and semilocal functionals. Physical Review B, 78(10). doi:10.1103/physrevb.78.104116Jeitschko, W., & Sleight, A. W. (1973). The crystal structure of HgMoO4 and related compounds. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 29(4), 869-875. doi:10.1107/s056774087300347

Puesta en marcha de un catálogo de demostraciones experimentales en asignaturas básicas

[EN] We present in this work the first steps carried out within a 2016-2017 PIME of the Vice Chancery for Studies, Quality and Accreditation the Polytechnic University of Valencia entitled "Active methodologies in basic subjects. A catalogue of experimental Physics demonstrations designed as teaching resources for the degree motivation". This project aims the design of a catalogue of simple experimental Physics demonstrations made with readily available low cost materials. It is intended to use this resource during lessons of theory and problems to demonstrate physical phenomena and their relationship to the theoretical models, favouring their understanding as well as to involve the students in the design of some of these experimental demonstrations through the implementation of small projects. The first designs of these experimental Physics demonstrations that will be implemented in a more general way the following courses are here presented.[ES] En este trabajo se muestran los primeros pasos que se han llevado a cabo dentro de un proyecto PIME de la convocatoria 2016-2017 del Vicerrectorado de Estudios, Calidad y Acreditación de la Universidad Politécnica de Valencia titulado “Metodologías activas en asignaturas básicas. Creación de un catálogo de demostraciones experimentales o proyectos como recursos didácticos para la motivación de título”. Este proyecto persigue como objetivo la creación de un catálogo de demostraciones experimentales sencillas, realizadas con materiales fácilmente disponibles y de bajo coste. Se pretende utilizar este recurso en las clases de teoría o problemas para poner de manifiesto fenómenos físicos y su relación con los modelos teóricos que los explican, favoreciendo su comprensión, así como involucrar a los estudiantes en alguna de estas demostraciones experimentales a través de pequeños proyectos. Aquí se presentan los primeros diseños de estas demostraciones experimentales que serán implantadas de forma más generalizada a partir de los siguientes cursos.Vilaplana Cerda, RI.; Rey Tormos, RMD.; Gomis Hilario, O.; Alba Fernández, J.; Manjón Herrera, FJ.; Cuenca Gotor, VP.; Monsoriu Serra, JA. (2017). Puesta en marcha de un catálogo de demostraciones experimentales en asignaturas básicas. En In-Red 2017. III Congreso Nacional de innovación educativa y de docencia en red. Editorial Universitat Politècnica de València. 74-88. https://doi.org/10.4995/INRED2017.2017.6794OCS748

Crystal structure of HgGa2Se4 under compression

We report on high-pressure x-ray diffraction measurements up to 17.2 GPa in mercury digallium selenide (HgGa2Se4). The equation of state and the axial compressibilities for the low-pressure tetragonal phase have been determined and compared to related compounds. HgGa2Se4 exhibits a phase transition on upstroke toward a disordered rock-salt structure beyond 17 GPa, while on downstroke it undergoes a phase transition below 2.1 GPa to a phase that could be assigned to a metastable zinc-blende structure with a total cation-vacancy disorder. Thermal annealing at low- and high-pressure shows that kinetics plays an important role on pressure-driven transitions.This study was supported by the Spanish government MEC under grants nos: MAT2010-21270-C04-01/03/04 and CTQ2009-14596-C02-01, by the Comunidad de Madrid and European Social Fund (S2009/PPQ-1551 4161893), by MALTA Consolider Ingenio 2010 project (CSD2007-00045), and by the Vicerrectorado de Investigacion y Desarrollo of the Universidad Politecnica de Valencia (UPV2011-0914 PAID-05-11 and UPV2011-0966 PAID-06-11). E.P.-G., J.L.-S., A.M., and P.R.-H. acknowledge computing time provided by Red Espanola de Supercomputacion (RES) and MALTA-Cluster.Gomis Hilario, O.; Vilaplana Cerda, RI.; Manjón, F.; Santamaría Pérez, D.; Errandonea, D.; Pérez González, E.; López Solano, J.... (2013). Crystal structure of HgGa2Se4 under compression. Materials Research Bulletin. 48:2128-2133. https://doi.org/10.1016/j.materresbull.2013.02.037S212821334

Intensidad de corriente que circula por un circuito RL en serie al abrir el interruptor

Funcion que dibuja la intensidad de corriente que circula por un cirtuito RL en serie en función del tiempo al abrir el interruptorhttps://laboratoriosvirtuales.upv.es/eslabon/Ejercicio?do=Circuito_RL_I_abrir_interruptorCGomis Hilario, O. (2011). Intensidad de corriente que circula por un circuito RL en serie al abrir el interruptor. http://hdl.handle.net/10251/921

Coeficiente de autoinducción de un solenoide toroidal (toroide)

Función que dibuja el coeficiente de autoinducción L de un solenoide toroidal en su interior en función de la distancia al centro del interior del mismo.https://laboratoriosvirtuales.upv.es/eslabon/Ejercicio?do=L_bobina_toroidalCGomis Hilario, O. (2011). Coeficiente de autoinducción de un solenoide toroidal (toroide). http://hdl.handle.net/10251/1379

Dilatación volumétrica de un sólido

Dilatación volumetrica de un sólido en función de la temperaturahttps://laboratoriosvirtuales.upv.es/eslabon/Ejercicio?do=Dilatacion_volumetrica_solidoCGomis Hilario, O. (2009). Dilatación volumétrica de un sólido. http://hdl.handle.net/10251/514