High isothermal magnetocaloric effect in La(Fe,Si)13 based alloys

Abstract

This work investigates the magnetocaloric effect (MCE) in LaFe_{11.6}Si_{1.4} and LaFe_{11.78}Mn_{0.41}Si_{1.32}H_{1.6} alloys under adiabatic {\Delta}T and isothermal {\Delta}Q conditions in a magnetic field of {\mu}_{0}H = 1.8 T. The studied samples exhibited high reproducibility of the {\Delta}Q-effect upon cyclic magnetic field application, which is of critical importance for magnetic cooling systems.The LaFe_{11.78}Mn_{0.41}Si_{1.32}H_{1.6} alloy demonstrate high values of the isothermal MCE, with a maximum {\Delta}Q = 3400 J/kg in a magnetic field of {\mu}0H = 1.8 T near the Curie temperature (TC) of 275 K. This value is 2.5 times higher than the well-known corresponding values for pure Gd at room temperature. Furthermore, the structural and magnetic properties of LaFe13-xSix-based alloys with Cr and Co additions were investigated using density functional theory calcula-tions. It was shown that the addition of Cr leads to a decrease in the equilibrium volume, i.e., to a com-pression of the crystal lattice, whereas Co addition causes its expansion. These changes are expected to increase or decrease the T_{C}, respectively.