Abstract
Electronic structure of SmCo7−x Tix alloy has been studied by means of the spin-polarized MS-Xα method. It is shown that a few of electrons are transferred to Sm(5d) orbital due to orbital hybridization between Sm and Co atoms. The exchange interaction between 5d-3d electrons is stronger, which is the main reason resulting in the long-range ferromagnetic order between Co and Sm atoms. The Curie temperature of SmCo7−x Tix is generally lower than that of pure Co metal, which may be explained by the weaker average of coupling strength between Co sites due to some negative exchange couplings occurring mainly at 2e site. The calculated results for the Sm5Co28Ti6 cluster may lead to a better understanding of why SmCo7−x Tix is stable phase. Since the negative interaction of 2e sites weakens and the bonding at E F strengthens with increasing Ti concentration, which result in the decrease in the free energy of the alloy, the stable ferromagnetic order forms inside SmCo7−x Tix. Considering the localization of 4f states and 5d moment arising from the orbital hybridization, the calculated moment is 9.47 μ B per formula unit that is in agreement with experiments.
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References
Kim, A. S., High temperature stability of SmTM magnets, J. Appl. Phys., 1998, 83(11): 6715–6717.
Liu, J. F., Zhang, Y., Dimitrov, D. et al., Microstructure and high temperature magnetic properties of Sm(Co, Cu, Fe, Zr)z (z = 6.7-9.1) permanent magnets, J. Appl. Phys., 1999, 85(5): 2800–2804.
Zhou, J., Skomski, R., Chen, C. et al., Sm-Co-Cu-Ti high-temperature permanent magnets, Appl. Phys. Lett., 2000, 77(10): 1514–1516.
Zhou, J., Al-Omari, I. A., Liu, J. P. et al., Structure and magnetic properties of SmCo7−x Tix with TbCu7-type structure, J. Appl. Phys., 2000, 87(9): 5299–5301.
Luo, J., Liang, J. K., Guo, Y. Q. et al., Crystal structure and magnetic properties of SmCo5.85Si0.90 compound, Appl. Phys. Lett., 2004, 84(16): 3094–3096.
Al-Omari, I. A., Yeshurun, Y., Zhou, J. et al., Magnetic and structural properties of SmCo7−x Cux alloys, J. Appl. Phys., 2000, 87(9): 6710–6712.
You, C. Y., Zhang, Z. D., Sun, X. K. et al., Phase transformation and magnetic properties of SmCo7−x Bx alloys prepared by mechanical alloying, J. Magn. Magn. Mater., 2001, 234: 395–400.
Huang, M. Q., Wallace, W. E., McHenry, M. et al., Structure and magnetic properties of SmCo7−x Zrx alloys (x = 0-0.8), J. Appl. Phys., 1998, 83(11): 6718–6720.
Jiang, C. B., Venkatesan, M., Gallagher, K. et al., Magnetic and structural properties of SmCo7−x Tix magnets, J. Magn. Magn. Mater., 2001, 236(10): 49–55.
Brooks, M. S. S., Eriksson, O., Johansson, B., 3d-5d band magnetism in rare transition metal intermetallics: LuFe2, J. Phys.: Condens. Matter., 1989, 1: 5861–5874.
Zhou, Y. Q., Modern Magnetic Materials Principle And Applications (in Chinese), Beijing: Chemical Industry Press, 2002, 480–483.
Zhang, C. W., Li, H., Dong, J. M. et al., Electronic structure and magnetic properties of SmCo7−x Tix, Science in China, Ser. G (in Chinese), 2005,35(3): 260–270.
Schwarz, K., Optimization of the statistical exchange parameter alpha for the free atoms H through Nb, Phys. Rev. B, 1972, 5(12): 2466–2468.
Dai, D. S., Qian, K. M., Ferromagnetism (in Chinese), Beijing: Science Press, 1998, 53–54.
Campbell, I. A., Indirect exchange for rare earths in metals, J. Phys. F: Metal Phys., 1972, 2: L47–L50.
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Zhang, C., Li, H., Dong, J. et al. Electronic structure and magnetic properties of SmCo7−x Tix . SCI CHINA SER G 49, 38–45 (2006). https://doi.org/10.1007/s11433-005-0074-z
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DOI: https://doi.org/10.1007/s11433-005-0074-z