材料期刊网

The compound MnAs_0.9P_0.1 exhibits a multistep magnetic order-order transition from a helimagnetic γ-phase with H_α-type magnetic order to a ferromagnetic β-phase at 80 K and then to a helimagnetic α-phase at 203 K. The γ-β transition exhibits the characteristics of a first-order transition with a thermal hysteresis as large as 6 K, while the β-α transition is of second order with a thermal hysteresis smaller than 2 K and without magnetic hysteresis. With these two successive helimagnetism-related transitions, magnetic-entropy changes of -2.1 J/(kg•K) at 203~K for a field change from 0 to 5 T and 0.1 J/(kg•K) at 83 K for a field change from 0 to 1 T are obtained. Investigation of the magnetocaloric effect associated with a transition from H_α-type magnetic order to FM order may open a new route to explore candidates for magnetic refrigeration.