The compound MnAs0.9P0.1 exhibits a multistep magnetic order-order transition from a helimagnetic γ-phase with Hα-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 Hα-type magnetic order to FM order may open a new route to explore candidates for magnetic refrigeration.
The light rare earth Pr/Ce-contained(Tb_(0.2)Pr_(0.8))_(1–x)Ce_(x)Fe_(1.93)(0≤x≤1.0)intermetallics were arc melted and magnetoelastic properties were investigated.The compounds of x≥0.40 are found to stabilize at ambient pressure in a single Laves phase with MgCu2-type C15 structure,which is attributed to the strong Ce 4f bonding.The mixed-valence behavior,with a support of the deviation from the linear Vegard’s law for both lattice parameter a and saturation magnetization M_(S),is observed at room temperature.The easy magnetization direction(EMD)was determined by the analysis of XRD on both magnetically aligned samples and the(440)splitting,that is,EMD lies toward<111>axis for x≤0.50 rotating to<110>for x=0.60,accompanied with the structural distortion from rhombohedral to orthorhombic.The substitution of Ce for Tb/Pr is conductive to the reduction of magnetocrystalline anisotropy,giving rise to an improvement of the low-field magnetostriction.The excellent magnetoelastic properties can be tailored by the Ce introduction,e.g.,the spontaneous magnetostriction coefficient λ_(111) as large as 1150×10^(−6) for x=0.40,and the low-field induced magnetostriction achieving a high value of λ_(a)=180×10^(−6) at 80 kA/m for x=0.60.The excellent magnetoelastic properties and the combination in high Pr-content with low cost,suggest promising prospects in applications.
Yihao ShenJinjun LiuQilin DingMingkun WangZhongbin PanJuan Du
