Abstract Ni50Mn37Sn13 and Ni50Mn35Sn15 epitaxial alloy thin films with two different compositions are grown on c plane sapphire substrate by pulsed laser deposition. The epitaxial relationship between untransformed L 2 1 and sapphire is α-Al2O3 [ 0 1 1 ¯ 0 ] ‖ L 2 1 [ 0 1 1 ]. The Curie temperatures of the films are 316 and 334 K, respectively. The microstructure of the films consists of untransformed austenite ( L 2 1 ) and three different martensite with L 1 0 , 4 O and 5 M structures. The relative volume fractions of four predominant phases are ∼50, 40, 5 and 5%, respectively at room temperature for both the films. The epitaxial L 2 1 phase grows under tensile strain on sapphire (0 0 0 1) substrate and favours the formation of predominantly L 1 0 over other martensite phases below the transition temperature. The interface between various untransformed and transformed phases are found to be coherent. The overall experimental magnetization of the thin films is slightly less than the theoretical values. Local HREELS spectra of Mn and Ni L 3 , 2 absorption edges confirm the presence of some non-magnetic phases in the structure particularly in 4 O and 5 M form of martensite might account for the observed differences with the theoretical value.

中文翻译：

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脉冲激光沉积外延Ni50Mn37/35Sn13/15 Heusler合金薄膜的显微结构和磁性能

摘要 通过脉冲激光沉积在c面蓝宝石衬底上生长了两种不同成分的Ni50Mn37Sn13和Ni50Mn35Sn15外延合金薄膜。未转变的L 2 1 与蓝宝石的外延关系为α-Al2O3 [ 0 1 1 ¯ 0 ] ‖ L 2 1 [ 0 1 1 ]。薄膜的居里温度分别为 316 和 334 K。薄膜的微观结构由未转变的奥氏体 (L 2 1 ) 和三种不同的具有 L 1 0 、4 O 和 5 M 结构的马氏体组成。在室温下，两种薄膜的四个主要相的相对体积分数分别为~50、40、5 和 5%。外延 L 2 1 相在蓝宝石 (0 0 0 1) 衬底上的拉伸应变下生长，并且有利于在低于转变温度的其他马氏体相上主要形成 L 1 0。发现各种未转化和转化相之间的界面是连贯的。薄膜的整体实验磁化强度略小于理论值。Mn 和 Ni L 3, 2 吸收边的局部 HREELS 光谱证实结构中存在一些非磁性相，特别是在 4 O 和 5 M 形式的马氏体中，这可能解释了观察到的与理论值的差异。