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要旨:
We present a pulsed magnetic field study on the magnetic and
magnetostriction properties of Ni-Mn-Z(Z=In, Sn, and Sb) based Heusler
shape-memory alloys. These materials generally display a field-induced
magnetostructural transition that could lead to an irreversible phase
transition, when measured near the martensitic transition temperature.
Here, we show that independently of the transition temperature, the
critical field for the phase transition sensitively depends on the
main-group element in the sample. Irrespective of their compositions,
all samples display a magnetization of around 2mu B/f.u. in the
martensite phase and about 6mu B/f.u. in the cubic austenite phase. Our
magnetic and magnetostriction measurements at low temperatures exhibit a
partial or complete arrest of the high-field austenite phase below the
reverse martensitic transition. This results in a large irreversibility
with a hysteresis width as high as 24 T. We introduce a theoretical
model to discuss the experimental results.
