LaFe_11.6Si_1.4/Pr₄₀Co₆₀ magnetocaloric composites for refrigeration near room temperature

The effect of Pr₄₀Co₆₀ addition on the structure, thermal conductivity, magnetic, magnetocaloric and mechanical properties of sintered LaFe_11.6Si_1.4/Pr₄₀Co₆₀ bulk composites were investigated. The addition of Pr–Co alloy has important effects on these properties due to the diffusion of Pr and Co into the La(Fe,Si)₁₃ phase during sintering. After 6 h of sintering at 1373 K, these composites exhibited a gradual increase in Curie temperature (T_C) from 220 K to near room temperature with relatively large maximum magnetic entropy change (–∆S_M)^max of 2.7–2.9 Jkg^–1 K^–1 under 0–2 T external magnetic field change. The diffusion of Pr and Co atoms into 1:13 majority phase facilitates 1:13 phase formation, while the Co content of the Pr-Co binder could be used to tune the T_C but resulting in the reduced (–∆S_M)^max in the composites. The composites exhibit high compressive strength (σ_bc)^max of up to 550 MPa and thermal conductivity (λ) of up to 10.64 Wm^–1 K^–1. Thus, these materials are promising candidates for near room temperature refrigeration.