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Title: Influence of annealing and phase decompostion on the magnetostructural transitions in Ni50Mn39Sn11

Abstract

Magnetic and structural transitions in the Ni{sub 50}Mn{sub 50-x}Sn{sub x} (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 ({approx}150 K below the reported B2 to L2{sub 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 < x < 25. Consistent with the magnetization data, transmission electron microscopy examination confirms that the alloy decomposed into two phases with x=20 and 1. From this result one can conclude that the martensitic transformation occurs only in those compositions where the single phase L2{sub 1} has been retained in a metastable state on cooling.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
977176
Report Number(s):
IS-J 7481
Journal ID: 0021-8979; TRN: US201009%%313
DOE Contract Number:  
DE-AC02-07CH11358
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 105; Journal Issue: 07A921
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALLOYS; ANNEALING; AUSTENITE; MAGNETIZATION; MARTENSITE; METASTABLE STATES; SHAPE; TRANSFORMATIONS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Yuhasz, W, Schlagel, D, Xing, Q, Dennis, K, McCallum, R, and Lograsso, T. Influence of annealing and phase decompostion on the magnetostructural transitions in Ni50Mn39Sn11. United States: N. p., 2009. Web.
Yuhasz, W, Schlagel, D, Xing, Q, Dennis, K, McCallum, R, & Lograsso, T. Influence of annealing and phase decompostion on the magnetostructural transitions in Ni50Mn39Sn11. United States.
Yuhasz, W, Schlagel, D, Xing, Q, Dennis, K, McCallum, R, and Lograsso, T. Fri . "Influence of annealing and phase decompostion on the magnetostructural transitions in Ni50Mn39Sn11". United States.
@article{osti_977176,
title = {Influence of annealing and phase decompostion on the magnetostructural transitions in Ni50Mn39Sn11},
author = {Yuhasz, W and Schlagel, D and Xing, Q and Dennis, K and McCallum, R and Lograsso, T},
abstractNote = {Magnetic and structural transitions in the Ni{sub 50}Mn{sub 50-x}Sn{sub x} (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 ({approx}150 K below the reported B2 to L2{sub 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 < x < 25. Consistent with the magnetization data, transmission electron microscopy examination confirms that the alloy decomposed into two phases with x=20 and 1. From this result one can conclude that the martensitic transformation occurs only in those compositions where the single phase L2{sub 1} has been retained in a metastable state on cooling.},
doi = {},
journal = {Journal of Applied Physics},
number = 07A921,
volume = 105,
place = {United States},
year = {2009},
month = {2}
}