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MA: Fachverband Magnetismus

MA 51: Caloric Effects in Ferromagnetic Materials

MA 51.2: Vortrag

Freitag, 22. März 2024, 10:00–10:15, H 2013

Impact of spin-entropy on the thermoelectric properties of a 2D magnet — •Alessandra Canetta — Institute of Condensed Matter and Nanosciences, Université catholique de Louvain (UCLouvain), 1348 Louvain-la-Neuve, Belgium

The heat-to-charge conversion efficiency of thermoelectric materials is closely linked to the entropy per charge carrier. Therefore, finding ways to increase this entropy could lead to new design strategies for highly efficient energy harvesters or spot-cooling devices. To this end, magnetic materials are a promising choice because their carrier entropy is boosted by a spin degree of freedom. To study this capability, a model magnetic system with high tunability of its magnetic order is required. The A-type antiferromagnet CrSBr fits these requirements and we investigate how spin entropy impacts heat-to-charge conversion in this 2D layered magnet. We perform simultaneous measurements of electrical conductance and thermocurrent while changing magnetic order using temperature and magnetic field as tuning knobs. We find a 10% decrease of the Seebeck coefficient when establishing antiferromagnetic order. We further reveal a drastic reduction of the Seebeck coefficient by one order of magnitude below a temperature of 40 K, which we attribute to a drop in spin entropy due to a spin-freezing process. Our results highlight the sizeable impact of spin entropy on thermoelectric properties and suggest thermoelectric measurements as a sensitive tool to study magnetic phase transitions in low-dimensional magnets.

Keywords: Two-dimensional; CrSBr; Thermoelectric; Entropy; Magnetism