Co掺杂Mn-Cr-Sb合金的低场可逆磁热效应

Low-field reversible magnetocaloric effect in Co-doped Mn-Cr-Sb alloys

本文研究了Mn(1.89-x)Cr_(0.11)Co_(x)Sb (x=0,0.04, 0.06)合金的磁相变与磁热效应.研究结果表明,合金在降温过程中发生了由亚铁磁相转变为反铁磁相的一级磁-弹性相变,相变过程中伴随着较窄的热滞后,约3–4 K. Co掺杂不仅能够增加磁-弹性相变的转变温度,而且能够抑制MnSb杂相的产生.利用直接测量绝热温变的方式表征了合金的磁热效应, Mn_(1.85)Cr_(0.11)Co_(0.04)Sb合金在1.5 T磁场下获得了高达-1.4 K的最大绝热温变和-1.2 K的可逆绝热温变.小的热滞后和大的低场可逆磁热效应使得该合金在磁制冷领域具有非常大的吸引力.

The magnetic phase transition and magnetocaloric effect in the Mn_(1.89-x)Cr_(0.11)Co_(x)Sb(x=0, 0.04, 0.06) alloys were studied in this work. Results show that the alloys undergo the first-order magneto-elastic phase transition from ferrimagnetic phase to antiferromagnetic phase on cooling, with very narrow thermal hysteresis, i.e., 3–4 K. Co doping cannot only enhance the transformation temperatures of magneto-elastic phase transition, but also avoid the formation of unfavorable Mn Sb phase. Direct measurements on the adiabatic temperature change △T_(ad) are employed to evaluate the magnetocaloric properties for the studied alloys. Under the field change of 1.5 T, the maximum △T_(ad) up to-1.4 K and the reversible △T_(ad) of-1.2 K can be achieved in the Mn1.85Cr0.11Co0.04Sb alloy. The combination of very small thermal hysteresis and large low-field reversible magnetocaloric effect makes the present alloys very attractive for the potential applications in magnetic refrigeration.