Three-dimensional critical behavior and nearly isotropic magnetic entropy change of Cr4PtGa17: A Half-Heusler-type compound with distorted Kagome planes

Abstract

We performed a systematic investigation on the magnetic properties of the single crystals of Cr4PtGa17, which is a Half-Heusler-type compound with distorted Kagome planes. The measured saturated and effective moments indicate an itinerant nature of the ferromagnetism at around 58 K with a Rhode-Wohlfarth ratio (RWR) equals 1.58 (1.57) for H∕∕ab (H∕∕c). Detailed analysis on critical behavior and the scaled magnetic entropy change verify the ferromagnetic transition at Tc ∼ 58 K is of a second order. Critical exponents are generated to be β = 0.300 ± 0.002 with Tc = 58.2 ± 0.1 K, γ = 1.211 ± 0.015 with Tc = 58.0 ± 0.1 K, and δ = 5.04 ± 0.03 at Tc = 58 K, exhibiting a three-dimensional critical behavior. The magnetic exchange coupling J(r) decreases spatially as J(r) ∼ r−4.86. Furthermore, the magnetic entropy change -ΔSM(T, H) are achieved, which features a maximum close to Tc with -ΔSMmax equals 0.413 (0.405) J kg−1K−1 under H∕∕ab (H∕∕c) with a field change of 5 T. The rotational magnetic entropy change ΔSMR is ∽ 0 J kg−1 K−1 at T > Tc showing an almost isotropic behavior, and is < 0.03 J kg−1K−1 at T < Tc exhibiting very weak anisotropy.