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要旨:
We have studied the magnetocaloric effect (MCE) in the shape-memory
Heusler alloy Ni50Mn35In15 by direct measurements in pulsed magnetic
fields up to 6 and 20 T. The results in 6 T are compared with data
obtained from heat-capacity experiments. We find a saturation of the
inverse MCE, related to the first-order martensitic transition, with a
maximum adiabatic temperature change of Delta T-ad = -7 K at 250K and a
conventional field-dependent MCE near the second-order ferromagnetic
transition in the austenitic phase. The pulsed magnetic field data allow
for an analysis of the temperature response of the sample to the
magnetic field on a time scale of similar to 10 to 100 ms, which is on
the order of typical operation frequencies (10-100 Hz) of magnetocaloric
cooling devices. Our results disclose that in shape-memory alloys, the
different contributions to the MCE and hysteresis effects around the
martensitic transition have to be carefully considered for future
cooling applications. (C) 2015 AIP Publishing LLC.
