Millisecond direct measurement of the magnetocaloric effect of a Fe_2P-based compound by the mirage effect

摘要

We present direct measurements of the magnetocaloric effect on a Fe_2P-based compound induced by a milliseconds pulsed magnetic field of 1T to test their possible use in high frequency (up to 100 Hz) thermomagnetic cycles. The reported measurements were performed with an innovative and versatile non-contact set up based on the mirage effect. The adiabatic temperature change of a MnFeP_(0.45)As_(0.55) sample is presented and compared with measurements performed varying the same magnetic field in a time interval of 1 s and 100 ms. These results demonstrate the absence of kinetic constraints in the first-order phase transition of this sample induced on the milliseconds time scale. The study of the materials' response to millisecond magnetic field pulses represents a fundamental test for the development of more powerful and efficient magnetic refrigerators.