High field X-ray diffraction studies on magnetic refrigerants.

In this paper, we review our recent results on magnetic refrigerants MnAs_{1-x}Sb_{x} and MnFeAs_{0.5}P_{0.5} by powder X-ray diffraction measurements in fields up to 5 T and in the temperature range from 8 to 320 K. MnAs shows a first-ordered structural transition with the volume expansion of 2.1% accompanied by a metamagnetic transition, but MnAs_{0.9}Sb_{0.1} exhibits an isostructural transition with the volume expansion of 1.1%. The cell volume of MnFeAs_{0.5}P_{0.5} slightly (-0.4%) and continuously decreases with increasing a magnetic field through the metamagnetic transition. [ABSTRACT FROM AUTHOR]