MATERTRANS : Vol. 44 (2003) , No. 12 pp.2509-2512

Influence of Fe and Co on Phase Transitions in Ni-Mn-Ga Alloys

Vladimir V. Khovailo¹⁾, Toshihiko Abe¹⁾, Viktor V. Koledov²⁾, Minoru Matsumoto³⁾, Hirokazu Nakamura⁴⁾, Ryunosuke Note⁵⁾, Makoto Ohtsuka³⁾, Vladimir G. Shavrov²⁾ and Toshiyuki Takagi⁴⁾

1) National Institute of Advanced Industrial Science and Technology, Tohoku Center
2) Institute of Radioengineering and Electronics of RAS
3) Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
4) Institute of Fluid Science, Tohoku University
5) Institute for Material Research, Tohoku University

(Received June 20, 2003)
(Accepted October 27, 2003)

Differential scanning calorimetry (DSC) and magnetic measurements were performed to study the influence of ferromagnetic 3-d transition elements Fe and Co on structural and magnetic properties of ferromagnetic shape memory alloys Ni₂MnGa. Addition of Fe or Co on the Ni sites decreases the temperature of martensitic phase transition T_m, whereas addition of Co on the Mn sites results in a considerable increase of T_m. Magnetic measurement revealed that Curie temperature T_C increases upon substitution of Fe or Co for Ni. This observation is of importance for design of high temperature ferromagnetic shape memory alloys.

Keywords:

quaternary Heusler alloys, martensitic transition, Curie temperature, ferromagnetic shape memory alloys