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arXiv · 2112.07970

Magneto-electric cooling rate of a multiferroic antiferromagnetic quantum spin system: the cumulative influence of the site-dependent magnetic and electric fields

William Degaulle Waladi Gueagni·Lionel Tenemeza Kenfack·Martin Tchoffo·Georges Collince Fouokeng·Lukong Cornelius Fai
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Abstract

The magneto-electrocaloric effect which can be defined as the coupling between magnetocaloric and electrocaloric effects attracts currently considerable attention due to the advantages provided by the caloric effect in designing solid-state refrigeration technologies. The magneto-electrocaloric effect of a multiferroic antiferromagnetic spin system with the Dzyaloshinskii Moriya (DM) interaction is investigated in this paper. The DM interaction is assimilated to a coupling between an external site-dependent electric field and a local electric polarization. The external magnetic is also considered as a site-dependent magnetic field. The spin-wave theory is used as a diagonalization method and through the canonical partition function, some thermodynamic properties such as the Boltzmann entropy and the specific heat capacity are obtained. Then, the adiabatic magnetic, electric, and magnetoelectric cooling rates are also derived. The graphs obtained for the adiabatic magnetic, electric, and magnetoelectric cooling rate show a characteristic behavior of the caloric or multi-caloric effect which is in good agreement with some experimental and theoretical works. Besides, the entropy response due to the variation of the external site-dependent magnetic field exhibits two anomalous entropy peaks indicating the existence of an intermediate phase tuneable by the magnetic and electric site-dependent parameters. Overall, it is demonstrated that the cumulative influence of the site-dependent magnetic and electric fields allows us not only to reveal quantum critical points hidden in a multiferroic quantum spin system but also to control the caloric or multi-caloric effect essential in the construction of solid-state refrigeration devices.

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William Degaulle Waladi Gueagni, Lionel Tenemeza Kenfack, Martin Tchoffo, Georges Collince Fouokeng, Lukong Cornelius Fai. 2021-12-15. Magneto-electric cooling rate of a multiferroic antiferromagnetic quantum spin system: the cumulative influence of the site-dependent magnetic and electric fields. https://arxiv.org/abs/2112.07970

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