Calorimetric Investigation of Magnetic Phase Transitions and Magnetocaloric Effects in Terbium

Abstract

This work presents a calorimetric study of the magnetic phase transitions in terbium under different temperatures and applied magnetic fields. From these measurements, transition temperatures have been obtained at TC = 222 K and at TN = 230 K. We report the magnetic phase diagram by tracking the change of these transitions driven by the application of a magnetic field. In addition, the transition entropy changes were obtained. The results reproduce the expected ferromagnetic, helical antiferromagnetic and paramagnetic phases and show thermal hysteresis between cooling and heating processes. The entropy associated with the phase transition decreases with increasing magnetic field, which is consistent with the progressive alignment of the magnetic moments. Although the experimental data agrees with previous studies, it is insufficient to confirm the existence of a fan or conical phase previously suggested.