Magnetocaloric effect for the altermagnetic candidate MnTe

Abstract

We experimentally investigate magnetocaloric effect for single crystals of MnTe altermagnet at the transition to the state with spontaneous spin polarization, i.e. well below the Néel temperature of MnTe. The isothermal magnetic entropy change $\hat{I}”S$ is calculated from the experimental magnetization curves by using Maxwell relation. We observe well-defined magnetocaloric effect as a narrow $\hat{I}”S$ peak around the cricital temperature $T_c\approx 81$~K, which is accompanied by sharp magnetization jump. This behavior is unusual for standard ferromagnetic transitions, so it confirms the predicted spin-orbit-induced spin polarization in the MnTe altermagnetic state.