Rotating Magnetocaloric Effect in First-order Phase Transition Material Gd5Si2Ge2

Rafael Almeida; Rodrigo Kiefe; Ricardo Moura Costa Pinto; João Sequeira Amaral; Kyle Dixon-Anderson; Yaroslav Mudryk; João Pedro Araújo; João Horta Belo

arXiv · 2601.13239

Rotating Magnetocaloric Effect in First-order Phase Transition Material Gd5Si2Ge2

Rafael Almeida·Rodrigo Kiefe·Ricardo Moura Costa Pinto·João Sequeira Amaral·Kyle Dixon-Anderson·Yaroslav Mudryk·João Pedro Araújo·João Horta Belo

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Abstract

The rotating magnetocaloric effect (RMCE) induced by self-demagnetization has been investigated in the giant magnetocaloric effect (GMCE) material Gd$_5$Si$_2$Ge$_2$. This shape-dependent effect had thus far only been reported in pure Gd, marking this as the first analysis of the effect in a sample with a magnetostructural first-order phase transition. By rotating the applied magnetic field vector while keeping its intensity constant, the demagnetizing field within a high-aspect ratio sample changes significantly, resulting in a RMCE. We characterize RMCE by determining the adiabatic temperature change ($\Delta T_{ad}^{rot}$) directly through temperature measurements, and the isothermal entropy change ($\Delta S_M^{rot}$) via magnetometry and magnetostatic simulations. We obtain a remarkable maximum $\Delta T_{ad}^{rot}$ of 1.77 K for a constant external field of 0.8 T, higher than that obtained under 1.0 T. The magnetostatic simulations not only corroborate the highly non-monotonous field-dependence of $|\Delta S_{M}^{rot}|$, which reaches 95\% of its maximum value at 0.8 T, 6.12 J K$^{-1}$ kg$^{-1}$ for the experimentally measured shape, but also estimate a 35\% increase in the maximum $|\Delta S_{M}^{rot}|$ up to 8.67 J K$^{-1}$ kg$^{-1}$ in a simulated shape with higher aspect ratio.

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Rafael Almeida, Rodrigo Kiefe, Ricardo Moura Costa Pinto, João Sequeira Amaral, Kyle Dixon-Anderson, Yaroslav Mudryk, João Pedro Araújo, João Horta Belo. 2026-01-19. Rotating Magnetocaloric Effect in First-order Phase Transition Material Gd5Si2Ge2. https://arxiv.org/abs/2601.13239

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