The magnetocaloric effect and low temperature specific heat of SmNi

The magnetocaloric effect (MCE) in a magnetic SmNi sample was evaluated from magnetization and heat capacity measurements. The MCE phenomena in the vicinity of magnetic phase transitions in terms of magnetic entropy change, ΔSM, and adiabatic temperature change, ΔTad, are reported. Isothermal magnetization σ(H)T=const measurements at several temperatures around the transition Tc=43K were carried out and used for ΔSMversus  TT calculations. A similar dependence of the magnetic entropy change −ΔSM=(SH−S0) was evaluated from heat capacity Cp(T)Cp(T) measurements under zero field and 5 T. The SmNi system provides magnetic refrigerants that induce an adiabatic cooling of about ΔTad≈1.2K during the magnetization process with a field of 5 T in the temperature range of 35–45 K. The temperature dependence of Cp(T)Cp(T) is analyzed in terms of the magnetic and the lattice contributions.

► Magnetization and specific heat measurements on an SmNi compound are reported.
► ΔH change from 0 to 5 T at T≈42K induces adiabatic cooling of ΔTad≈1.2K.
► A low temperature anomaly at T=9.75K on Cp(T)Cp(T) was discovered as a spin-reorientation transition (SRT).
► Thermal excitation within the three crystal field energy doublets of Sm is proved.