By means of a mean-field model extended to include magnetovolumic effects we study the effect of external fields on the thermal response characterized either by the isothermal entropy change and/or the adiabatic temperature change. The model includes two different situations induced by the magnetovolumic coupling. (i) A first order para- ferromagnetic phase transition that entails a volume change. (ii) An inversion of the effective exchange interaction that promotes the occurrence of an antiferromagnetic phase at low temperatures. In both cases, we study the magneto- and baro-caloric effects as well as the corresponding cross caloric responses. By comparing the present theoretical results with available experimental data for several materials we conclude that the present thermodynamical model reproduces the general trends associated with the considered caloric and cross caloric responses.
Barocaloric and Magnetocaloric Effects in Fe49Rh51
本文报道了在外加静水压和磁场作用下Fe $_{49}$ Rh $_{51}$的反铁磁（AFM）-铁磁（FM）相变的量热研究。结果表明，存在一个巨大的压热效应，在这种合金，一个新的功能特性，增加了磁热和弹性热效应，以前报道的这种合金。所有的热效应都源于AFM/FM转变，其中包括体积、磁化强度和熵的变化。转变温度对流体静压和磁场的强烈敏感性赋予该合金优异的压热和磁热强度值（$|ΔS|$/$Δp$ $\sim$ 12 J kg $^{-1}$ K $^{-1}$ kbar $^{-1}$ and $|ΔS|$/$μ_0ΔH$ $\sim$ 12 J kg $^{-1}$ K $^{-1}$ T $^{-1}$）。已经发现压热和磁热效应两者在压力和磁场循环时是可再现的。这种良好的再现性和大的热强度使得Fe-Rh合金在弱外部刺激下特别适合固态冷却技术。
Quantification of electronic and magnetoelastic mechanisms of first-order magnetic phase transitions from first principles: application to caloric effects in La(Fe$_x$Si$_{1-x}$)$_{13}$
Residual stress induced stabilization of martensite phase and its effect on the magneto-structural transition in Mn rich Ni-Mn-In/Ga magnetic shape memory alloys
