Co_(100-x)Mn_x合金在GaAs(001)表面的生长结构和磁性的实验研究

EPITAXIAL STRUCTURES AND MAGNETIC PROPERTIES OF Co\-\{100- x \}Mn\- x ALLOYS ON GaAs(001) SURFACE 

对Ｃｏ１００ － ｘ Ｍｎｘ 合金在ＧａＡｓ（００１） 表面的分子束外延生长、晶体结构和磁学性质进行了研究．结果表明，当０ ＜ ｘ ＜ ４４ 时，Ｃｏ１００ － ｘ Ｍｎ ｘ 合金薄膜是体材料中不存在的体心立方（ｂｃｃ）结构，并且具有较强的铁磁性，当４４ ＜ ｘ ＜ ７８ 时，Ｃｏ１００ － ｘ Ｍｎ ｘ 合金薄膜最初为ｂｃｃ 结构，随着厚度的增加，逐渐从ｂｃｃ 向面心立方（ｆｃｃ） 结构转化，最后成为完全的ｆｃｃ 结构，薄膜具有较弱的铁磁性，当７８ ＜ ｘ ＜ １００ 时，Ｃｏ１００－ ｘＭｎ ｘ 合金为ｆｃｃ 结构。

The epitaxial growth crystal structure and magnetism of Co\-\{100- x \}Mn\- x alloys grown on GaAs(001) substrate have been studied by using reflection high energy electron diffraction,X\|ray diffraction and surface magneto\|optic Kerr effect.For 0< x <42,the epitaxial films have the single\|crystal body\|centered cubic(bcc) structure,which has never been found in the bulk Co\-\{100- x \}Mn\- x alloys.They show strong ferromagnetism.For 42< x <78,in the first and final stages of growth,the Co\-\{100- x \}Mn\- x alloy exists in bodycentered cubic(bcc)and face\|centered cubic(fcc)phases respectively,and the coexistence of the bcc and fcc structures is observed in the middle stage.It is proved by using wedge samples that only the bcc phase contributes to the ferromagnetism.For x >78,the epitaxial alloys have fcc structure and show no Ferromagnetism.