Spin Stiffness Constant of Half-metallic Ferrimagnet in Mn-based Heusler Alloys

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• 作者：Rie Y. Umetsu^a ; ^b ; ¹ ; ^{rieume@imr.tohoku.ac.jp" class="auth_mail" title="E-mail the corresponding author} ; Takeshi Kanomata^c ; ² ; ^{kanomata@mail.tohoku-gakuin.ac.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：half-metal ferrimagnets ; spin stiffness constant ; spontaneous magnetization ; the Curie temperature ; exchange interaction
• 刊名：Physics Procedia
• 出版年：2015
• 出版时间：2015
• 年：2015
• 卷：75
• 期：Complete
• 页码：890-897
• 全文大小：524 K

文摘

In order to investigate the spin stiffness constant, D, of Mn-based Heusler alloys with half-metallic density of states, magnetic measurements were properly carried out. The Curie temperature, T_C, of Mn₂VAl, Mn₅₀V₂₀Al₃₀ and Mn₂CoGa were 768, 738 and 740 K, respectively. The value of D was evaluated from the temperature, T, dependence of the spontaneous magnetization in each specimen below 150 K, where linear dependence of T^3/2 was observed. The D values for these materials were obtained to be 5.34, 4.38 and 5.67 meV·(nm)² and significantly larger than that for Co-based Heusler alloys reported previously. The strong exchange interaction would be the reason that the Mn-based Heusler alloys indicate high T_C even though they have not so large total magnetic moment comparing to that of Co-based Heusler alloys.