2002/12/18 by J. Enkovaara, Jussi Enkovaara, Oleg Heczko +3 · 2 citations
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Magnetic and transport properties of perovskites and related materials #Paleontology and Evolutionary Biology #Shape Memory Alloy Transformations #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.67.212405
4 pages, 3 figures
arxiv created 2002/12/18 · openalex publication_date 2003/06/16 · arxiv updated 2009/11/30 · openalex created_date 2017/05/26 · openalex updated_date 2026/08/01
Ni-Mn-Ga is interesting as a prototype of a magnetic shape-memory alloy showing large magnetic field induced strains. We present here results for the magnetic ordering of Mn-rich Ni-Mn-Ga alloys based on both experiments and theory. Experimental trends for the composition dependence of the magnetization are measured by a vibrating sample magnetometer (VSM) in magnetic fields of up to several tesla and at low temperatures. The saturation magnetization has a maximum near the stoichiometric composition and it decreases with increasing Mn content. This unexpected behaviour is interpreted via first-principles calculations within the density-functional theory. We show that extra Mn atoms are antiferromagnetically aligned to the other moments, which explains the dependence of the magnetization on composition. In addition, the effect of Mn doping on the stabilization of the structural phases and on the magnetic anisotropy energy is demonstrated.