Large low-field magnetic refrigeration in ferromagnetic insulator EuTi_0.9V_0.1O₃

Abstract

Magnetic properties and the magnetocaloric effect have been studied in a ferromagnetic compound EuTi_0.9V_0.1O₃ by magnetization and heat capacity measurements. With the application of a magnetic field, the spin entropy is strongly suppressed and a large magnetic entropy change is observed near the Curie temperature TC=4.54K. The values of entropy change ΔSm, adiabatic temperature change, and magnetic cooling capacity are 41.4 J kg⁻¹K⁻¹, 17.4 K, and 577 J kg⁻¹, respectively, for a field change of 0–7T. This compound also shows a large magnetocaloric effect at low magnetic fields. In particular, −ΔSm reaches as high as 11 and 20 Jkg⁻¹K⁻¹ for field changes of 0–1 and 0–2 T, respectively. These values of magnetocaloric parameters are significantly larger than that reported for several potential low-temperature magnetic refrigerants. The low-field large magnetocaloric effect, together with the absence of thermal and field hysteresis, makes the insulating EuTi_0.9V_0.1O₃ compound a promising candidate for refrigeration below 30K.