Magnetic Structure Of R 2 Coga 8 (r = Gd, Tb, And Dy): Structural Tuning Of Magnetic Properties In Layered Ga-based Intermetallic Compounds

In this work we have determined the magnetic structure of R2CoGa8 (R= Gd, Tb, and Dy) intermetallic compounds using x-ray resonant magnetic scattering in order to study the evolution of the anisotropic magnetic properties along the series for R= Gd-Tm. The three compounds have a commensurate antiferromagnetic spin structure with a magnetic propagation vector τâ- = (12,12,12) and a Néel temperature of approximately 20, 28.5, and 15.2 K for R= Gd, Tb, and Dy, respectively. The critical exponent β obtained from the temperature dependence of the magnetic peaks suggest a three-dimensional universality class for the three compounds. Comparing the simulated and integrated intensities we conclude that the magnetic moment direction is in the ab plane for the Gd2CoGa8 compound and parallel to the c axis for the Tb2CoGa8 and Dy2CoGa8 compounds. The evolution of the magnetic properties of the R2CoGa8 series for R= Gd-Tm is discussed taking into account the indirect Ruderman-Kittel-Kasuya-Yoshida interaction and crystalline-electric field effects. The comparison between the reported magnetic properties of the Ga-based compounds with those for the In-based isostructural family reveals differences in their exchange couplings that contribute to the understanding of the role of the f-electron magnetism in these classes of materials. © 2014 American Physical Society.8911Thompson, J., Fisk, Z., (2012) J. Phys. Soc. Jpn., 81, p. 011002. , JUPSAU 0031-9015 10.1143/JPSJ.81.011002Movshovich, R., Jaime, M., Thompson, J.D., Petrovic, C., Fisk, Z., Pagliuso, P.G., Sarrao, J.L., (2001) Phys. Rev. Lett., 86, p. 5152. , PRLTAO 0031-9007 10.1103/PhysRevLett.86.5152Sarrao, J., Morales, L., Thompson, J., Scott, B., Stewart, G., Wastin, F., Rebizant, J., Lander, G., (2002) Nature (London), 420, p. 297. , NATUAS 0028-0836 10.1038/nature01212Curro, N.J., Sarrao, J.L., Thompson, J.D., Pagliuso, P.G., Kos, S., Abanov, Ar., Pines, D., (2003) Phys. Rev. Lett., 90, p. 227202. , 10.1103/PhysRevLett.90.227202Hegger, H., Petrovic, C., Moshopoulou, E.G., Hundley, M.F., Sarrao, J.L., Fisk, Z., Thompson, J.D., (2000) Phys. Rev. Lett., 84, p. 4986. , PRLTAO 0031-9007 10.1103/PhysRevLett.84.4986Thompson, J., Movshovich, R., Fisk, Z., Bouquet, F., Curro, N., Fisher, R., Hammel, P., Jaime, M., (2001) J. Magn. Magn. Mater., p. 5. , JMMMDC 0304-8853 10.1016/S0304-8853(00)00602-8Pagliuso, P., Garcia, D., Miranda, E., Granado, E., Serrano, R., Giles, C., Duque, J., Thompson, J., (2006) J. Appl. Phys., 99, pp. 08P703. , JAPIAU 0021-8979 10.1063/1.2176109Lora-Serrano, R., Giles, C., Granado, E., Garcia, D.J., Miranda, E., Agüero, O., Mendonça Ferreira, L., Pagliuso, P.G., (2006) Phys. Rev. B, 74, p. 214404. , PRBMDO 1098-0121 10.1103/PhysRevB.74.214404Adriano, C., Lora-Serrano, R., Giles, C., De Bergevin, F., Lang, J.C., Srajer, G., Mazzoli, C., Pagliuso, P.G., (2007) Phys. Rev. B, 76, p. 104515. , PRBMDO 1098-0121 10.1103/PhysRevB.76.104515Pagliuso, P.G., Thompson, J.D., Hundley, M.F., Sarrao, J.L., Fisk, Z., (2001) Phys. Rev. B, 63, p. 054426. , PRBMDO 1098-0121 10.1103/PhysRevB.63.054426Pagliuso, P.G., Thompson, J.D., Hundley, M.F., Sarrao, J.L., (2000) Phys. Rev. B, 62, p. 12266. , PRBMDO 0163-1829 10.1103/PhysRevB.62.12266Bao, W., Pagliuso, P.G., Sarrao, J.L., Thompson, J.D., Fisk, Z., Lynn, J.W., (2001) Phys. Rev. B, 64, p. 020401. , R). PRBMDO 0163-1829 10.1103/PhysRevB.64.020401Granado, E., Pagliuso, P.G., Giles, C., Lora-Serrano, R., Yokaichiya, F., Sarrao, J.L., (2004) Phys. Rev. B, 69, p. 144411. , PRBMDO 1098-0121 10.1103/PhysRevB.69.144411Adriano, C., Giles, C., Coelho, L., Faria, G., Pagliuso, P., (2009) Physica B, 404, p. 3289. , PHYBE3 0921-4526 10.1016/j.physb.2009.07.127Adriano, C., Aliouane, N., Mardegan, J.R.L., Coelho, L.N., Escovi, R.V., Pagliuso, P.G., Giles, C., (unpublished)Johnson, R.D., Frawley, T., Manuel, P., Khalyavin, D.D., Adriano, C., Giles, C., Pagliuso, P.G., Hatton, P.D., (2010) Phys. Rev. B, 82, p. 104407. , PRBMDO 1098-0121 10.1103/PhysRevB.82.104407Fisk, Z., Remeika, J., Gschneider, K.A., Eyring, L., (1989) Handbook on the Physics and Chemistry of Rare Earths, p. 53. , edited by, Vol. 12 (Elsevier, AmsterdamJoshi, D.A., Nagalakshmi, R., Dhar, S.K., Thamizhavel, A., (2008) Phys. Rev. B, 77, p. 174420. , PRBMDO 1098-0121 10.1103/PhysRevB.77.174420Giles, C., Yokaichiya, F., Kycia, S., Sampaio, L., Ardiles-Saravia, D., Franco, M., Neuenschwander, R., (2003) J. Synchrotron Rad., 10, p. 430. , JSYRES 0909-0495 10.1107/S0909049503020958Vaillant, F., (1977) Acta Cryst. A, 33, p. 967. , ACACBN 0567-7394 10.1107/S0567739477002307Hill, J., McMorrow, D., (1996) Acta Cryst. A, 52, p. 236. , ACACEQ 0108-7673 10.1107/S0108767395012670Joly, Y., (2001) Phys. Rev. B, 63, p. 125120. , PRBMDO 1098-0121 10.1103/PhysRevB.63.125120Gibbs, D., Grubel, G., Harshman, D.R., Isaacs, E.D., McWhan, D.B., Mills, D., Vettier, C., (1991) Phys. Rev. B, 43, p. 5663. , PRBMDO 0163-1829 10.1103/PhysRevB.43.5663Collins, M.F., (1989) Magnetic Critical Scattering, , (Oxford University Press, Oxford)Wills, A., (2000) Physica B, p. 680. , PHYBE3 0921-4526 10.1016/S0921-4526(99)01722-6Detlefs, C., Islam, A.H.M.Z., Goldman, A.I., Stassis, C., Canfield, P.C., Hill, J.P., Gibbs, D., (1997) Phys. Rev. B, 55, pp. R680. , PRBMDO 0163-1829 10.1103/PhysRevB.55.R680Nandi, S., Su, Y., Xiao, Y., Price, S., Wang, X.F., Chen, X.H., Herrero-Martín, J., Brückel, Th., (2011) Phys. Rev. B, 84, p. 054419. , PRBMDO 1098-0121 10.1103/PhysRevB.84.054419Blundell, S., (2001) Magnetism in Condensed Matter, , Oxford Master Series in Condensed Matter Physics (Oxford University Press, Oxford)The density of states at the Fermi level for Gd 2 IrIn 8 was estimated using the electronic contribution to the heat capacity γ measured for the isomorphous reference compound La 2 IrIn 8Kovalev, O.V., Stokes, H.T., Hatch, D.M., (1993) Representations of the Crystallographic Space Groups, , 2nd ed., edited by (Gordon and Breach Science Publishers, Yverdon, Switzerland

Magnetic Properties Of Gdt2zn20 (t=fe, Co) Investigated By X-ray Diffraction And Spectroscopy

We investigate the magnetic and electronic properties of the GdT2Zn20 (T=Fe and Co) compounds using x-ray resonant magnetic scattering (XRMS), x-ray absorption near-edge structure (XANES), and x-ray magnetic circular dichroism (XMCD). The XRMS measurements reveal that GdCo2Zn20 has a commensurate antiferromagnetic spin structure with a magnetic propagation vector τ - =(12,12,12) below the Néel temperature (TN∼5.7 K). Only the Gd ions carry a magnetic moment forming an antiferromagnetic structure with magnetic representation Γ6. For the ferromagnetic GdFe2Zn20 compound, an extensive investigation was performed at low temperature and under magnetic field using XANES and XMCD. A strong XMCD signal of about 12.5% and 9.7% is observed below the Curie temperature (TC∼85K) at the Gd L2 and L3 edges, respectively. In addition, a small magnetic signal of about 0.06% of the jump is recorded at the Zn K edge, suggesting that the Zn 4p states are spin polarized by the Gd 5d extended orbitals. © 2016 American Physical Society.93

Magnetic field dependent cycloidal rotation in pristine and Ge doped CoCr2O4

We report a soft x ray resonant magnetic scattering study of the spin configuration in multiferroic thin films of Co0.975Ge0.025Cr2O4 Ge CCO and CoCr2O4 CCO under low and high magnetic fields from 0.2 to 6.5 T. A characterization of Ge CCO at a low magnetic field was performed, and the results were compared with those of pure CCO. The ferrimagnetic phase transition temperature TC amp; 8776;95K and the multiferroic transition temperature TS amp; 8776;27K in Ge CCO are comparable with those observed in CCO. In Ge CCO, the ordering wave vector qq0 observed below TS is slightly larger compared with that of CCO, and unlike CCO, the diffraction intensity consists of two contributions that show a dissimilar x ray polarization dependence. In Ge CCO, the coercive field observed at low temperatures was larger than the one reported for CCO. In both compounds, an unexpected reversal of the spiral helicity, and therefore the electric polarization, was observed on simply magnetic field cooling. In addition, we find a change in the helicity as a function of momentum transfer in the magnetic diffraction peak of Ge CCO, indicative of the presence of multiple magnetic spiral

Structural Distortion And Magnetic Order In The Intermetallic Eu 3ir4sn13 Compound

In this work, we have investigated the low temperature structural distortion and magnetic properties of the Eu3Ir4Sn 13 Remeika cubic phase compound using X-ray powder diffraction (XRD), X-ray resonant magnetic scattering (XRMS) and neutron diffraction. X-ray scattering revealed that the peak observed in electrical resistivity and heat capacity measurements is related to a structural distortion at T*=57.1 K. This crystallographic distortion characterized by the arising of a propagation vector q=(0,(1/2),(1/2)) is due to a displacement of the Sn ions at the Sn1Sn212 polyhedron. In addition, the neutron diffraction experiments performed on a single crystal of Eu3Ir4Sn13 exhibit an antiferromagnetic coupling below TN=10.1 K where we observe a commensurate magnetic propagation vector τ=(0,(1/2),(1/2)) identical to the one observed for the structural distortion. © 1965-2012 IEEE.49846524655Remeika, J., Espinosa, G., Cooper, A., Barz, H., Rowell, J., McWhan, D., Vandenberg, J., Woolf, L., A new family of ternary intermetallic superconducting/magnetic stannides (1980) Solid State Commun., 34 (12), pp. 923-926Israel, C., Bittar, E., Agüero, O., Urbano, R., Rettori, C., Torriani, I., Pagliuso, P., Borges, H., Crystal structure and low-temperature physical properties of R Sn ( R Ce LaIr Co) intermetallics (2005) Physica B: Condensed Matter, 359, pp. 251-253Sato, H., Fukuhara, T., Iwakawa, S., Aoki, Y., Sakamoto, I., Takayanagi, S., Wada, N., Magnetic and transport properties of Ir Sn (1993) Physica B: Condensed Matter, 186, pp. 630-632Takayanagi, S., Sato, H., Fukuhara, T., Wada, N., Two magnetic transitions in Ce Ir Sn (1994) Physica B: Condensed Matter, 199, pp. 49-51Nagoshi, C., Sugawara, H., Aoki, Y., Sakai, S., Kohgi, M., On-Imaru, H.S.T., Sakakibara, T., Anomalous phase transitions in the heavy fermion compound Ce Ir Sn (1986) Physica B, 136 B, pp. 432-435Ferreira, L.M., Bittar, E., Pires, M., Urbano, R., Agüero, O., Torriani, I., Rettori, C., Baggio-Saitovich, E., Antiferromagnetic ordering of divalent Eu in Eu Ir Sn intermetallic compound (2006) Physica B: Condensed Matter, 384 (1-2), pp. 332-335Nagoshi, C., Yamamoto, R., Kuwahara, K., Sagayama, H., Kawana, D., Kohgi, M., Sugawara, H., Arai, M., Magnetic and transport properties of Ir Sn with unique crystal structure (2006) J. Physical Soc. Japan, 75 (4), p. 044710. , AprAoki, Y., Fukuhara, T., Sugawara, H., Sato, H., Valence of Eu ion in Eu Ir Sn at low temperatures (1996) J. Physical Soc. Japan, 65, pp. 1005-1009Pires, M.A., Ferreira, L.M., Duque, J.G.S., Urbano, R.R., Aguero, O., Torriani, I., Rettori, C., Pagliuso, P.G., Crystal structure and physical properties of Eu ion in Sn intermetallic antiferromagnet (2006) J. Appl. Phys., 99, pp. 08J311Hodeau, J., Marezio, M., Remeika, J., Chen, C., Structural distortion in the primitive cubic phase of the superconducting/magnetic ternary rare-earth rhodium stannides (1982) Solid State Commun., 42 (2), pp. 97-102Agüero, O., (2007) Estudo Estrutural de Sistemas Nanoestruturados Com-postos Intermetálicos e Cobaltitas, , Ph.D. dissertation, Unicamp, Campinas, BrazilGiles, C., Yokaichiya, F., Kycia, S., Sampaio, L., Ardiles-Saravia, D., Franco, M., Neuenschwander, R., High-resolution x-ray diffraction beamline at the LNLS for the study of charge, orbital and magnetic structures (2003) J. Synchrotron Rad., 10, pp. 430-434Hill, J.P., McMorrow, D.F., Resonant exchange scattering: Polarization dependence and correlation function (1996) Acta Crystallographica Sec. A, 52 (2), pp. 236-244. , MarMiraglia, S., Hodeau, J.L., Marezio, M., Laviron, C., Ghedira, M., Espinosa, G.P., Nature of the structural distortion and of the chemical bondingin Sn (Yb, Ca, Sr, and Th) (1986) J. Solid State Chemistry, 63, pp. 358-368Hodeau, J., Chenavas, J., Marezio, M., Remeika, J., The crystal structure of Sn, a new ternary superconducting stan-nide (1980) Solid State Commun., 36 (10), pp. 839-845Beaurepaire, E., Bulou, H., Scheurer, F., Kappler, J.-P., (2010) Magnetism and Synchrotron Radiation: New Trends Ser. Proceedings in Physics, , Berlin, Germany: SpringerBordet, P., Hodeau, J.L., Wolfers, P., Miraglia, S., Benoit, A., Marezio, M., Remeika, J.P., Magnetic structures of Sn and Sn Sn (2005) Physica B, B, pp. 359-361Blundell, S., (2001) Magnetism in Condensed Matter, , New York, NY, USA: Oxford Univ. PressBalakrishnan, G., Nagarajan, R., Paghdar, S.K., Gupta, L.C., Vijayaraghavan, R., Eu and Sn Mossbauer studies in the Sn (1990) Physica B: Phys. Condensed Matter, 165, pp. 227-22

Hidden Charge Order in an Iron Oxide Square Lattice Compound

Since the discovery of charge disproportionation in the FeO2 square lattice compound Sr3Fe2O7 by Mössbauer spectroscopy more than fifty years ago, the spatial ordering pattern of the disproportionated charges has remained hidden to conventional diffraction probes, despite numerous x ray and neutron scattering studies. We have used neutron Larmor diffraction and Fe K edge resonant x ray scattering to demonstrate checkerboard charge order in the FeO2 planes that vanishes at a sharp second order phase transition upon heating above 332 K. Stacking disorder of the checkerboard pattern due to frustrated interlayer interactions broadens the corresponding superstructure reflections and greatly reduces their amplitude, thus explaining the difficulty of detecting them by conventional probes. We discuss the implications of these findings for research on hidden order in other material