Inverse magnetocaloric effect in the uniaxial paramagnet with non-Kramers ions

Abstract

It has been shown that, in a uniaxial paramagnet with non-Kramers ions with a spin of S = 1 and single-ion anisotropy of the easy-plane type (DS_Z²), there is a low-field (μ₀H ≤ D) and low-temperature (k_BT < 0.68D) region in which the isothermal magnetization along the hard direction H||OZ increases the magnetic entropy by ΔS_M(T, ΔH = H_f - H_i > 0) > 0 and the adiabatic magnetization along the same direction reduces the sample temperature by ΔT_ad(T, ΔH > 0) < 0 (inverse magnetocaloric effect (MCE)). The main features of the inverse MCE in uniaxial paramagnets with large spins (S = 2, 3, …) of the non-Kramers ions have been discussed.