Investigation of field-controlled magnetocaloric switching effect in single crystal antiferromagnetic MnBi2Te4

Being the first intrinsic antiferromagnetic (AFM) topological insulator (TI), MnBi2Te4, has garnered significant attention as an ideal platform for realizing diverse exotic topological quantum states. However, little is known about the magnetocaloric properties of MnBi2Te4 to date. In this work, we report the magnetocaloric effect, rotating magnetocaloric effect, and magnetocaloric switching effect of single-crystal MnBi2Te4. Under 0-9 T, the maximum magnetic entropy changes (-Delta SM) obtained are 2.5 J kg- 1 K- 1 and 2.1J kg- 1 K- 1, when H & Vert;c and H & Vert;ab, respectively. Furthermore, the anisotropy in the-Delta SM between the two crystallographic orientations gives MnBi2Te4 single crystals a rotational magnetocaloric effect. The sample exhibits a rotating entropy change of 0.4J kg- 1 K- 1 under a magnetic field of 9 T as the magnetic field is rotated from the ab plane to the c axis. More importantly, MnBi2Te4 exhibits a coexistence of conventional and inverse magnetocaloric effects by switching between them at a specific temperature and magnetic field, that is, the magnetocaloric switching effect. Moreover, the switching temperature of MnBi2Te4 can be modulated by changing the magnetic field, so that it is suitable for various constant-temperature baths. This study provides a meaningful clue for the design and exploration of high performance MCE-based constant-temperature devices.