Er1-xTmxCr2Si2(0≤x≤0.4)低场驱动大磁熵变高性能磁制冷研究OA

The effect of Tm doping on the magnetic phase transition and magnetocaloric effect(MCE)of ErCr2Si2-based compounds were systematically investigated.A series of polycrystalline Er1-xTmxCr2Si2(0≤x≤0.4)samples were successfully synthesized by the arc-melting method.X-ray powder diffraction combined with Rietveld refinement indicated that all samples crystallized in the ThCr2Si2-type tetragonal structure with space group I4/mmm.It was found that with increasing Tm concentration,the saturation magnetization(MS)decreased from 7.7 μB(x=0)to 6.8 μB(x=0.4).Under a low magnetic field(Δμ0H)change of 0-1 T,the x=0.1 sample exhibited the optimal magnetocaloric performance,with maximum magnetic entropy change(-ΔSMmax)of 19.7 J/(kg·K),representing an enhancement of 18.7%compared with the reported undoped ErCr2Si2(-ΔSMmax=16.6 J/(kg·K)).Moreover,the saturation driving magnetic field HS corresponding to the magnetic entropy change decreased from 0.45 T to 0.4 T.Tm doping also significantly broadened the effective refrigeration operating temperature window(Tope).Under a magnetic field change of ∆μ0H=0-5 T,Tope expanded from 14.1 K(2-16.1 K)for x=0 to 17.3 K(2-19.3 K)for x=0.4,corresponding to an increase of approximately 22.7%.In addition,both the thermal hysteresis loss(ΔThys)and the average magnetic hysteresis loss(Wave)decreased with increasing Tm concentration,from 0.33 K and 2.28 J/kg at x=0 to 0.22 K and 0.89 J/kg at x=0.4,representing reductions of about 33.3%and 60.9%,respectively.Arrott plots,power-law critical exponent fitting,and the universal behavior of the reduced magnetic entropy change curves consistently demonstrated that this system exhibited typical second-order magnetic phase transition characteristics.Its small thermal and magnetic hysteresis losses were considered beneficial for practical applications in industrial magnetic refrigeration.