Structural Studies on Some 3d Heusler Alloys (I)

Abstract

3d 천이원소 Heusler합?鳧? 보통 X₂Y Z (X=Cu, Ni, Co, Fe, Y=Mn, Cr, V, Ti, Sc등, Z=ⅢA나 ⅣA족 원소)로 쓰여지며 천이금속의 자기적 성질을 규명하는데 또 결정적인 면에서도 많은 흥미를 끌고 있다. 최근에는 X₃-?? ?? Z로 쓸 수 있는 비정수 조성을 갖는 Heusler합금에 대한 연구가 이루어지고 있다. 본 논문에서는 X₃-?? Y?? Z 및 X₂Y₂-?? Z??의 두가지 형태의 비정수 조성 합금의 결정구조를 조사하여 보았다.

첫 번째 형의 합금인 Co₃-?? Mn?? Si에 있어서는 n≤1.0인 영역에서 L2₁구조(Heusler형)를 갖고 있었음이 밝혀졌으며 n이 1.1을 초과함에 따라 입방의 L2₁구조 외에 비입방상이 나타나기 시작하였다. 격자상수는 대체적으로 5,654Å 부근에서 별로 변하지 않았다. 두 번째 형의 합금인 Fe₂V₂-??Al??에서는 조사한 영역(n≤0.5)에서 전부 L2₁구조를 보여주었으며 n=0.5에서 5.795Å인 격자상수는 n이 증가함에 따라 감소 현상을 보였다. Fe₂ Ti₂-?? Al??에 대하여도 조사가 이루어졌다.

3d transition metal Heusler alloys, usually denoted as X₂Y Z (X=Cu, Ni, Co, Fe, Y=Mn, Cr, V, Ti, Sc, Z=ⅢA elements) are magnetically and crystallographically interesting. In recent years, some research works have been done on structural and magnetic properties of non-stoichiometric Heusler alloys, X₃-?? Y?? Z. In this paper, two types of non-stoichiometric alloys are reported about their structural studies. One is X₃-??Y?? Z and the other X₂Y₂-?? Z??.

Co₃-?? Mn?? Si series, the former type, showed L2₁ structure (Heusler type) in the range n≤1.0 and a second phase began to appear as n exceeded 1.1. Lattice parameters remained almost constant around 5,654A over the range studied. Fe₂V₂-?? Al?? series, the latter type, showed L2₁ structure in the investigated range n≤0.5 and lattice parameters increased with A1 concentration decreasing. Studies were also made on Fe₂ Ti₂-?? Al?? series.

3d transition metal Heusler alloys, usually denoted as X₂Y Z (X=Cu, Ni, Co, Fe, Y=Mn, Cr, V, Ti, Sc, Z=ⅢA elements) are magnetically and crystallographically interesting. In recent years, some research works have been done on structural and magnetic properties of non-stoichiometric Heusler alloys, X₃-?? Y?? Z. In this paper, two types of non-stoichiometric alloys are reported about their structural studies. One is X₃-??Y?? Z and the other X₂Y₂-?? Z??.

Co₃-?? Mn?? Si series, the former type, showed L2₁ structure (Heusler type) in the range n≤1.0 and a second phase began to appear as n exceeded 1.1. Lattice parameters remained almost constant around 5,654A over the range studied. Fe₂V₂-?? Al?? series, the latter type, showed L2₁ structure in the investigated range n≤0.5 and lattice parameters increased with A1 concentration decreasing. Studies were also made on Fe₂ Ti₂-?? Al?? series.