Influence of annealing and phase decomposition on the magnetostructural transitions in Ni50Mn39Sn11

TitleInfluence of annealing and phase decomposition on the magnetostructural transitions in Ni50Mn39Sn11
Publication TypeJournal Article
Year of Publication2009
AuthorsYuhasz WM, Schlagel DL, Xing Q, Dennis KW, McCallum RW, Lograsso TA
Journal TitleJournal of Applied Physics
Volume105
Pages07a921
Date Published04/01
ISBN Number0021-8979
Accession NumberISI:000266633500246
Keywordsmagnetic-properties, ni-mn-ga, shape-memory alloys, transformations
Abstract

Magnetic and structural transitions in the Ni50Mn50-xSnx (x=10-25) ferromagnetic shape memory alloys are currently of interest. As in Ni-Mn-Ga, these alloys feature high-temperature austenite and low-temperature martensite phases, where the magnetic state is strongly composition dependent. To study the role of chemical ordering in fine-tuning their magnetostructural properties, they were first annealed for 4 weeks/1223 K to achieve structural and compositional homogeneity, and were then further annealed for 1 week (similar to 150 K below the reported B2 to L2(1) transition) at 773 K to increase the degree of chemical ordering. For x=11, this anneal resulted in a dramatic change in the magnetic ordering temperature. Following the 1223 K anneal, the sample exhibited ferromagnetic ordering at 140 K. After the 773 K anneal, the ferromagnetic transition is at 350 K, a characteristic of the ferromagnetic austenite phase with 15

URL<Go to ISI>://000266633500246
DOI10.1063/1.3067855