Desenvolvimento e avaliação de uma fonte DC de alta tensão para utilização em sistema de deposição de filmes finos por pulverização catódica

RESUMO O trabalho em questão está relacionado ao projeto e construção de uma fonte de alta tensão em corrente contínua utilizando materiais e dispositivos adquiridos no comércio local visando sua aplicação no processo de pulverização catódica. Essa técnica permite a deposição de filmes finos de metais, óxidos e nitretos sobre substratos sólidos. Como teste de funcionamento e aplicação da fonte DC, com a mesma instalada em canhão de pulverização em alto vácuo, filmes finos de diferentes espessuras de cobre, aço inoxidável 304 e tungstênio foram depositados e estudados. Análise de espessura, morfologia, e resistência elétrica e resistividade foram conduzidas. Filmes com resistividade elétrica dependente das espessuras foram obtidos. A fonte DC se mostrou confiável em operação e permite a deposição de uma infinidade de materiais nas mais diferentes espessuras sobre vários tipos de substratos

Gas And Pressure Sensors Based On Multi-wall Carbon Nanotubes: Study Of Sensing Mechanisms

Mechanisms of gas sensing in sensors based on multi-wall carbon nanotubes decorated by Ti nanoparticles have been studied. Tests were performed with N 2, Ar and O 2 at low temperatures. Chemi-resistor sensor configurations with supported and suspended nanotubes were tested. Contributions from two gas sensing mechanisms (chemical and electrothermal) were shown to depend strongly on a sensor configuration. For suspended nanotubes, their heating by Joule effect results in much stronger and faster sensor response to oxygen. Oxygen detection with high sensitivity in this case was achieved at room temperature. Copyright © 2010 American Scientific Publishers All rights reserved.83488492Rodríguez, A., Fernández-García, M., (2007) Synthesis, Properties, and Applications of Oxide Nanomaterials, , JohnWiley, Inc., New JerseyMeyyappan, M., Nanotubes, C., (2005) Science and Applications, , CRC Press LLC, FloridaVairavapandian, D., Vichchulada, P., Lay, M.D., (2008) Anal Chim. Acta, 626, p. 119Kong, J., Chapline, M.G., Dai, H., (2001) Adv. Matt., 13, p. 1384Boul J, P.J., Liu, E.T., Huffman, M.C.B., Ericson, L.M., Chiang, I.W., Smith, K.A., Colbert, D.T., Smalley, R.E., (1999) Chem. Phys. Lett., 310, p. 367Star, A., Joshi, V., Skarupo, S., Thomas, D., Gabriel, J.-C.P., (2006) J. Phys. Chem. B, 110, p. 21014Horváth, Z.E., Koós, A.A., Kertész, K., Moinar, G., Vértesy, G., Bein, M.C., Frigyes, T., Biró, L.P., (2008) Appl Phys. A, 93, p. 495Chen, R., Bangsaruntip, S., Drouvalakis, K.A., Kam, N.W.S., Shim, M., Li, Y., Kim, W., Dai, H., (2003) PNAS, 100, p. 4984Park, K.N., Na, P.S., So, H.-M., Kim, J.-J., Kim, H., Kong, K.-J., Chang, H., Lee, J.-O., (2006) Nanotechnology, 17, p. 496Yu Kupriyanov, L., (1996) Handbook of Sensors and Actuators, 4. , Elsevier Science, AmsterdanKorotcenkov, G., (2007) Mater. Sci. Eng. B, 139, p. 1Fu, D., Xu L J, Y., Chen, L.Y., Mhaisalkar, S.G., Boey, F.Y.C., Lin, T.W., Moochhala, S., (2007) Carbon, 45, p. 1911Moshkalev, S.A., Leon, J., Verissimo, C., Vaz, A.R., Flacker, A., De Moraes, M.B., Swart, J.W., (2008) J. Nano Res., 3, p. 25Bourton, B., Miko, C., Forró, L., Glattli, D.C., Batchold, A., (2004) Phys. Rev. Lett, 93, p. 176806Vaz, A.R., Macchi, M., Leon, J., Moshkalev, S.A., Swart, J.W., (2008) J. Mater. Sci., 43, p. 3429Wei, J., Zhu, H., Wu, D., Wei, B., (2004) Appl. Phys. Lett., 84, p. 4869Pop, E., Mann, D.A., Goodson, K.E., Dai, H., (2007) J. Appl. Phys., 101, p. 093710Pop, E., Mann, D., Cao, J., Wang, Q., Goodson, K., Dai, H., (2005) Phys. Rev. Lett., 95, p. 155505Berber, S., Kwon, Y., Tomanek, D., (2000) Phys. Rev. Lett., 84, p. 4613Gelamo, R.V., Rouxinol, F.P., Verissimo, C., Vaz, A.R., De Bica Moraes, M.A., Moshkalev, S.A., (2009) Chem. Phys. Lett., 482, p. 30

Low-temperature Gas And Pressure Sensor Based On Multi-wall Carbon Nanotubes Decorated With Ti Nanoparticles

Multi-wall carbon nanotubes decorated by Ti nanoparticles were used for gas (N2, Ar, O2) sensing at low temperatures. Chemiresistor sensor configurations with supported and suspended nanotubes were tested. Two gas sensing mechanisms (chemical and electrothermal) were demonstrated, with their relative contributions strongly depending on the sensor configuration. For suspended nanotubes, heating by Joule effect results in strong enhancement of chemical sensitivity to oxygen. © 2009 Elsevier B.V. All rights reserved.4824-6302306Meyyappan, M., (2005) Carbon Nanotubes: Science and Applications, , CRC Press LLC, FloridaKong, J., Chapline, M.G., Dai, H., (2001) Adv. Mater., 13, p. 1384Boul, P.J., (1999) Chem. Phys. Lett., 310, p. 367Kim, B.-K., (2006) Nanotechnology, 17, p. 496Lu, Y., Li, J., Han, J., Ng, H.-T., Binder, C., Partridge, C., Meyyappan, M., (2004) Chem. Phys. Lett., 391, p. 344Star, A., Joshi, V., Skarupo, S., Thomas, D., Gabriel, P.J.-C., (2006) J. Phys. Chem. B, 110, p. 21014Ao, Z.M., Yang, J., Li, S., Jiang, Q., (2008) Chem. Phys. Lett., 461, p. 276Kupriyanov, L.Yu., (1996) Handbook of Sensors and Actuators, 4. , Elsevier Science, AmsterdamKorotcenkov, G., (2007) Mater. Sci. Eng. B, 139, p. 1Rodríguez, A., Fernández-García, M., (2007) Synthesis, Properties, and Applications of Oxide Nanomaterials, , John-Wiley Inc., New JerseyKolmakov, A., Moskovits, M., (2004) Annu. Rev. Mater. Sci., 34, p. 151Strelcov, E., Dmitriev, S., Button, B., Cothren, J., Sysoev, V., Kolmakov, A., (2008) Nanotechnology, 19, p. 355502Prades, J.D., (2008) Appl. Phys. Lett., 93, p. 123110Fu, D., (2007) Carbon, 45, p. 1911Li, J., Lu, Y., Ye, Q., Cinke, M., Han, J., Meyyappan, M., (2003) Nano Lett., 3, p. 929Lu, Y., Partridge, C., Meyyappan, M., Li, J., (2006) J. Electroanal. Chem., 593, p. 105Moshkalev, S.A., Leon, J., Verissimo, C., Vaz, A.R., Flacker, A., de Moraes, M.B., Swart, J.W., (2008) J. Nano Res., 3, p. 25Kawano, T., Chiamori, H.C., Suter, M., Zhou, Q., Sosnowchik, B.D., Lin, L., (2007) Nano Lett., 7, p. 3686Vaz, A.R., Macchi, M., Leon, J., Moshkalev, S.A., Swart, J.W., (2008) J. Mater. Sci., 43, p. 3429Kuo, C.Y., Chan, C.L., Gau, C., Liu, C.W., Shiau, S.H., Ting, J.H., (2007) IEEE Trans. Nanotechnol., 6, p. 63Pop, E., Mann, D., Cao, J., Wang, Q., Goodson, K., Dai, H., (2005) Phys. Rev. Lett., 95, p. 155505Pop, E., Mann, D.A., Goodson, K.E., Dai, H., (2007) J. Appl. Phys., 101, p. 093710Shen, S., Narayanaswamy, A., Chen, G., (2009) Nano Lett., 9, p. 2909Cai, X., Akita, S., Nakayama, Y., (2004) Thin Solid Films, 464-465, p. 364Gelamo, R.V., in preparatio

Multiwall Carbon Nanotubes Decorated With Metal Oxide Nanoparticles For Gas Sensing Applications

Experimental procedures have been developed to prepare carbon nanotubes (CNTs) decorated by metal oxides nanoparticles for gas sensing applications. For decoration of carbon nanotubes with Sn and Cu oxides, the concentration of precursors and time of sonication were found to be crucial parameters, to control the size and density of nanoparticles on the nanotubes surface. In the case of CNTs decorated with Ti oxides, the pH value of the solution was found to play a key role in the final size of the nanoparticles. The material decorated with SnO2 was tested with H2S and changes in the conductivity showed the potential of this material for gas sensing application. © The Electrochemical Society.231237242Kong, J., Franklin, N., Zhou, C., Chapline, M., Peng, S., Cho, K., Dai, H., (2000) Science Science, 287, p. 622Zhao, L.P., Gao, L., (2004) J. Mater. Chem, 14, p. 1001Sainbury, T., Fitzmaurice, D., (2004) Chem. Mater, 16, p. 3780Wong, Y.M., Kang, W.P., Davidson, J.L., Wisitsora-at, A., Soh, K.L., (2003) Sens. Actuators B, 93, p. 327Qi, P.F., Vermesh, O., Grecu, M., Javey, A., Wang, Q., Dai, H.J., Peng, S., Cho, K.J., (2003) Nano Lett, 3, p. 347Comini, E., Faglia, G., Sberveglieri, G., Pan, Z.W., Wang, Z.L., (2002) Appl. Phys. Lett, 81, p. 1069McAleer, J.F., Moseley, P.T., Norris, J.O.W., Williams, D.E., Taylor, P., (1987) Mater. Chem. Phys, 17, p. 577Sberveglieri, G., Comini, E., Faglia, G., Atashbar, M.Z., Wlodarski, W., (2000) Sensors Actuators B, 66, p. 139Kolmakov, A., Zhang, Y.X., Cheng, G.S., Moskovits, M., (2003) Adv. Mater, 15, p. 997Xie, J., Zhang, N., Varadan, V.J., (2006) Smart Mater. Struct, 15, p. 5. ,

Characterization Of Si:o:c:h Films Fabricated Using Electron Emission Enhanced Chemical Vapour Deposition

Silicon-based polymers and oxides may be formed when vapours of oxygen-containing organosilicone compounds are exposed to energetic electrons drawn from a hot filament by a bias potential applied to a second electrode in a controlled atmosphere in a vacuum chamber. As little deposition occurs in the absence of the bias potential, electron impact fragmentation is the key mechanism in film fabrication using electron-emission enhanced chemical vapour deposition (EEECVD). The feasibility of depositing amorphous hydrogenated carbon films also containing silicon from plasmas of tetramethylsilane or hexamethyldisiloxane has already been shown. In this work, we report the deposition of diverse films from plasmas of tetraethoxysilane (TEOS)-argon mixtures and the characterization of the materials obtained. The effects of changes in the substrate holder bias (VS) and of the proportion of TEOS in the mixture (XT) on the chemical structure of the films are examined by infrared-reflection absorption spectroscopy (IRRAS) at near-normal and oblique incidence using unpolarised and p-polarised, light, respectively. The latter is particularly useful in detecting vibrational modes not observed when using conventional near-normal incidence. Elemental analyses of the film were carried out by X-ray photoelectron spectroscopy (XPS), which was also useful in complementary structural investigations. In addition, the dependencies of the deposition rate on VS and XT are presented. © 2007 Elsevier B.V. All rights reserved.5165803806Wang, J., de Moraes, M.A.B., Landers, R., Trasferetti, B.C., (2002) Plasmas Polym., 7, p. 227de Moraes, M.A.B., Durrant, S.F., Rouxinol, F.P.M., (2001) Thin Solid Films, 398-399, p. 591Gelamo, R.V., Bica de Moraes, M.A., Trasferetti, B.C., Rouxinol, F.P.M., Davanzo, C.U., (2005) Chem. Mater., 17, p. 5789Greenler, R.G., (1966) J. Chem. Phys., 44, p. 310Berreman, D.W., (1963) Phys. Rev., 130, p. 2193Kirk, C.T., (1988) Phys. Rev., B, 38, p. 1255Jurgens-Kowal, T.A., Rogers, J.W., (1998) J. Phys. Chem., B, 102, p. 2193Wolfe, D.M., Hinds, B.J., Wang, F., Lucovsky, G., Ward, B.L., Xu, M., Nemanich, R.J., Maher, D.M., (1999) J. Vac. Sci. Technol., A, Vac. Surf. Films, 17, p. 2170Smith, A.L., (1977) Applied Infrared Spectroscopy, p. 286. , Wiley, New YorkLucovsky, G., Tsu, D.V., (1987) J. Vac. Sci. Technol., A, Vac. Surf. Films, 5, p. 2231Silverstein, R.M., Bassler, G.C., Morrill, T.C., (1967) Spectrometric Identification of Organic Compounds, , John Wiley, New York (Ch. 3)Pliskin, W.A., (1977) J. Vac. Sci. Technol., 14, p. 1054Nilsen, K., Wautier, H., Danforth, S.C., (1986) Ceramic Powder Science, Advances in Ceramics, 21, p. 537. , Messing G., Mazdiyani K., McCauley J., and Haber R. (Eds), American Ceramic Society, Westerville, OHAlmeida, R.M., Pantano, C.G., (1990) J. Appl. Phys., 68, p. 4225Durrant, S.F., Castro, S.G., Cisneros, J.I., Cruz, N.C., Bica de Moraes, M.A., (1996) J. Vac. Sci. Technol., 14, p. 118Yasuda, H., Marsh, H.C., Bumgarner, O., Morosoff, N., (1975) J. Appl. Polym. Sci., 19, p. 2845Nefedov, V.I., Salyn, Ya.V., Leonhardt, G., Scheibe, R., (1977) J. Electron Spectrosc., 10, p. 121Wagner, C.D., Riggs, W.M., Davis, L.E., Moulder, J.F., (1979) Handbook of X-ray Photoelectron Spectroscopy, pp. 52.f. , Muilenberg G.E. (Ed), Perkin-Elmer Corp, Eden Prairie, MinnesotaWagner, C.D., (1978) J. Vac. Sci. Technol., 15, p. 518Lee, H.J., Yang, C.S., Chi, C.K., (2004) Mat. Sci. Forum, 449, p. 473Mabboux, P.Y., Gleason, K.K., (2005) J. Electrochem. Soc., 152, pp. F7Oh, K.S., Yu, Y.H., Choi, C.K., Lee, K.M., (2006) J. Korean Phys. Soc., 48, p. 168

Erratum: Magnetism In Gd-w Films (journal Of Applied Physics (2008) 103 (093916))

[No abstract available]1031

Developments In Hot-filament Metal Oxide Deposition (hfmod)

Hot-filament metal oxide deposition (HFMOD) is a variant of conventional hot-filament chemical vapor deposition (HFCVD) recently developed in our laboratory and successfully used to obtain high-quality, uniform films of MOx, WOx and VOx. The method employs the controlled oxidation of a filament of a transition metal heated to 1000 °C or more in a rarefied oxygen atmosphere (typically, of about 1 Pa). Metal oxide vapor formed on the surface of the filament is transported a few centimetres to deposit on a suitable substrate. Key system parameters include the choice of filament material and diameter, the applied current and the partial pressures of oxygen in the chamber. Relatively high film deposition rates, such as 31 nm min- 1 for MoOx, are obtained. The film stoichiometry depends on the exact deposition conditions. MoOx films, for example, present a mixture of MoO2 and MoO3 phases, as revealed by XPS. As determined by Li+ intercalation using an electrochemical cell, these films also show a colouration efficiency of 19.5 cm2 C- 1 at a wavelength of 700 nm. MOx and WOx films are promising in applications involving electrochromism and characteristics of their colouring/bleaching cycles are presented. The chemical composition and structure of VOx films examined using IRRAS (infrared reflection-absorption spectroscopy), RBS (Rutherford backscattering spectrometry) and XPS (X-ray photoelectron spectrometry) are also presented. © 2007 Elsevier B.V. All rights reserved.5165789793Somani, P.R., Radhakrishnan, S., (2002) Mater. Chem. Phys., 77, p. 117Julien, C., Nazri, G.A., Guesdon, J.P., Gorenstein, A., Khelfa, A., Hussain, O.M., (1994) Solid State Ion., 73, p. 319Wiesener, K., Scheider, W., Ilic, D., Steger, E., Hallmeier, K.H., Brackmann, E., (1987) J. Power Sources, 20, p. 157Makimura, Y., Rougier, A., Tarascon, J.M., (2006) Appl. Surf. Sci., 252, p. 4593Penin, N., Rugier, A., Laffont, L., Poizot, P., Tarascon, J.M., (2006) Sol. Energy Mater. Sol. Cells, 90, p. 422Korosec, R.C., Bukovec, P., (2006) Acta Chim. Slov., 53, p. 136Zayim, E.O., Tepehan, F.Z., (2004) Key Eng. Mater., 264-268, p. 435Corbella, C., Vives, M., Pingol, A., Porqueras, I., Person, C., Bertran, E., (2003) Solid State Ion., 165, p. 15Takasu, Y., Onoue, S., Kameyama, K., Murakami, Y., Yahikozawa, K., (1994) Electrochim. Acta, 39, p. 1993Schiavone, L.M., Smith, W.C.D., Beni, G., Shay, J.L., (1981) J. Electrochem. Soc., 128, p. 1339Patil, P.S., Kawar, R.K., Sadale, S.B., (2005) Appl. Surf. Sci., 249, p. 367Aegerter, M.A., Schmitt, M., Guo, Y.P., (2002) Int. J. Photoenergy, 4, p. 1Huang, Y.S., Zhang, Y.Z., Hu, X.F., (2002) J. Inorg. Mater., 17, p. 632Macek, M., Orel, B., (1998) Sol. Energy Mater. Sol. Cells, 54, p. 121Richardson, T.J., Rubin, M.D., (2001) Electrochim. Acta, 46, p. 2119Yonghong, Y., Jiayu, Z., Peifu, G., Xu, L., Jinfa, T., (1997) Thin Solid Films, 298, p. 197Cantão, M.P., Cisneros, J.I., Torresi, R.M., (1995) Thin Solid Films, 259, p. 70Trasferetti, B.C., Davanzo, C.U., da Cruz, N.C., Bica de Moraes, M.A., (2000) Appl. Spectrosc., 54, p. 687Scarmínio, J., Lourenço, A., Gorenstein, A., (1997) Thin Solid Films, 302, p. 66Ivanova, T., Gesheva, K.A., Popkirov, G., Ganchev, M., Tzvetkova, E., (2005) Mater. Sci. Eng., B, Solid-State Mater. Adv. Technol., 119, p. 232Gesheva, K., Szekeres, A., Ivanova, T., (2003) Sol. Energy Mater. Sol. Cells, 76, p. 563Yang, T.S., Ling, Z.R., Wong, M.S., (2005) Appl. Surf. Sci., 252, p. 2029Solarska, R., Alexander, B.D., Augustynski, J., (2006) C. R. Chim., 9, p. 301Meda, L., Breitkopf, C., Haas, T.E., Kirss, R.U., (2002) Thin Solid Films, 402, p. 126Avellaneda, C.O., Bulhões, L.O.S., (2003) Solid State Ion., 165, p. 117Mahan, A.H., Parilla, P.A., Jones, K.M., Dillon, A.C., (2005) Chem. Phys. Lett., 413, p. 88Ottviano, L., Pennisi, A., Simone, F., Salvi, A.M., (2004) Opt. Mater., 27, p. 307Surca, A., Orel, B., Drazic, G., Pihlar, B., (1999) J. Electrochem. Soc., 146, p. 232Al-Kuhaili, M.F., Khawaja, E.E., Ingram, D.C., Durrani, S.M.A., (2004) Thin Solid Films, 460, p. 30Bica de Moraes, M.A., Trasferetti, B.C., Rouxinol, F.P., Landers, R., Durrant, S.F., Scarmínio, J., Urbano, A., (2004) Chem. Mater., 16, p. 513Scarmínio, J., Bica de Moraes, M.A., Dias, R.C., Rouxinol, F.P., Durrant, S.F., (2003) Electrochem. Solid-State Lett., 6, pp. H9Berreman, D.W., (1963) Phys. Rev., 130, p. 219

Infrared Spectroscopy Investigation Of Various Plasma-deposited Polymer Films Irradiated With 170 Kev He+ Ions

This work illustrates the advantages of using p-polarized radiation at an incidence angle of 70° in contrast to the conventional unpolarized beam at normal (or near-normal) incidence for the infrared spectroscopic study of polycarbosilane, polysilazane and polysiloxane thin films synthesized by plasma enhanced chemical vapor deposition (PECVD) and subsequently irradiated with 170 keV He+ ions at fluences from 1 × 1014 to 1 × 1016 cm-2. Several bands not seen using the conventional mode could be observed in the polarized mode. © 2006 Elsevier B.V. All rights reserved.2491-2 SPEC. ISS.162166Jones, B.J., Barklie, R.C., Khan, R.U.A., Carey, J.D., Silva, S.R.P., (2001) Diamond Relat. Mater., 10, p. 993Li, D.J., Cui, F.Z., Gu, H.Q., Zhao, J., (1998) Appl. Surf. Sci., 126, p. 1Rangel, E.C., da Cruz, N.C., Bica de Moraes, M.A., Kretly, L.C., (1998) Nucl. Instr. and Meth. B, 141, p. 211Pearce, H.A., Sheppard, N., (1976) Surf. Sci., 59, p. 205Berreman, D.W., (1963) Phys. Rev., 132, p. 2193Trasferetti, B.C., Davanzo, C.U., Bica de Moraes, M.A., (2003) J. Phys. Chem. B, 107, p. 10699Pliskin, W.A., (1977) J. Vac. Sci. Technol., 14, p. 1064Anderson, D.R., (1974) Analysis of Silicones, , Smith A.L. (Ed), John Wiley and Sons, New YorkSmith, L., Anderson, D.R., (1984) Appl. Spectrosc., 38, p. 822Lucovsky, G., (1998) J. Non-Cryst. Solids, 227, p. 1Bellamy, L.J., (1975) The Infra-Red Spectra of Complex Molecules, , Chapman and Hall, LondonRau, C., Kulisch, W., (1994) Thin Solid Films, 249, p. 28Sugahara, S., Kadoya, T., Usami, K., Hattori, T., Matsumura, M., (2001) J. Electrochem. Soc., 148, pp. F120Fleischer, H., McKean, D.C., (1999) J. Phys. Chem. A, 103, p. 727Trasferetti, B.C., Davanzo, C.U., Bica de Moraes, M.A., (2004) Macromolecules, 37, p. 459Yasuda, H., (1985) Plasma Polymerization, , Academic Press, New YorkVenkatesan, T., Wolf, T., Allara, D., Wilkens, B.J., Taylor, G.N., (1983) Appl. Phys. Lett., 43, p. 934Pivin, J.C., Colombo, P., (1997) J. Mater. Sci., 32, p. 6163Kirk, C.T., (1988) Phys. Rev. B, 38, p. 1255Srivastava, S., Avasthi, D.K., Pivin, J.C., (2002) Nucl. Instr. and Meth. B, 191, p. 718Rangel, E.C., da Cruz, N.C., Bica de Moraes, M.A., Lepienski, C.M., (2000) Surf. Coat. Technol., 127, p. 93Wolfe, D.M., Hinds, B.J., Wang, F., Lucovsky, G., Ward, B.L., Xu, M., Nemanich, R.J., (1999) J. Vac. Sci. Technol. A, 17, p. 2170van Orden, A., Saykally, R.J., (1998) Chem. Rev., 98, p. 2313Fuente, E., Menendez, J.A., Diez, M.A., Suarez, D., Montes-Moran, M.A., (2003) J. Phys. Chem. B, 107, p. 6350Mani, K.K., Ramani, R., (1974) Phys. Stat. Sol., 61, p. 659Nemanich, R.J., Lucovsky, G., Solin, S.A., (1977) Solid State Commun., 23, p. 11

Carbon Nanotube- And Graphene-based Micro-sensors And Reactors

[No abstract available]171177Rao, C.N.R., Deepak, F.L., Gundiah, G., Govindaraj, A., (2003) Prog. Solid State Chem, 31, p. 5Kuchibhatla, S.V.N.T., Karakoti, A.S., Bera, D., Seal, S., (2007) Prog. Mater Sci., 52, p. 699Kolmakov, A., Moskovits, M., (2004) Annu. Rev. Mater. Res., 34, p. 151Yamazoe, N., Sakai, G., Shimanoe, K., (2003) Catal. Surv. Asia., 7, p. 63Shin, W.C., Besser, R.S., (2006) J. Micromech. Microeng., 16, p. 731Comini, E., Baratto, C., Faglia, G., Ferroni, M., Vomiero, A., Sberveglieri, G., (2009) Prog. Mater. Sci., 54, p. 1Gelamo, R.V., Rouxinol, F.P., Verissimo, C., Vaz, A.R., Bica de Moraes, M.A., Moshkalev, S.A., (2009) Chem. Phys. Lett., 482, p. 302Gelamo, R.V., Rouxinol, F.P., Verissimo, C., Bica de Moraes, M.A., Moshkalev, S.A., (2010) Sens. Lett., 8, p. 488Goldoni, A., Petaccia, L., Lizzit, S., Larciprete, R., (2010) J. Phys. Condens. Matter., 22, p. 013001Zevallos-marques, A., Brasil, M.J., Iikawa, F., Verissimo, C., Abbaspourrad, A., Moshkalev, S.A., Alves, O.L., (2010) J. Appl. Phys., 108, p. 083501. , 6pAbgrall, P., Nguyen, N.T., (2008) Anal. Chem., 80, p. 2326Dai, L., Soundarrajan, P., Kim, T., (2002) Pure Appl. Chem., 74, p. 1753Tiggelaar, R.M., Van Male, P., Berenschot, J.W., Gardeniers, J.G.E., Oosterbroek, R.E., De Croon, H.M.J.M., Schouten, J.C., Elwenspoek, M.C., (2005) Sens. Actuators A, 119, p. 196Rouxinol, F.P., Gelamo, R.V., Amici, R.G., Vaz, A., Moshkalev, S.A., (2010) Appl. Phys. Lett., 97, p. 253104. , 3

Magnetic Properties Of Metastable Gdcr Alloys

We report on the magnetization, magnetocaloric effect, magnetic ordering temperatures, saturation magnetic moments and anisotropy of sputter-deposited GdxCr1-x alloys with Gd atomic concentrations, x, ranging from 0.13 to 0.52. The complex magnetic nature of the GdCr films was revealed from the M×H isotherms, which do not show saturation even at an applied field of 70 kOe and a temperature of 2 K and do not exhibit a linear behavior at higher temperatures. For some of the samples, the isotherms were used to determine the isothermal entropy variation as a function of temperature, for a change of 50 kOe in the applied magnetic field. The saturation magnetic moment varies with x and follows the dilution law, implying that the Cr atoms do not contribute to the total moment of the GdCr alloys. Both static magnetization and dynamic susceptibility measurements reveal the existence of a magnetic glassy behavior in the alloys, which occurs below a freezing temperature. 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