Breathing pyrochlore magnet CuGaCr$_{4}$S$_{8}$: Magnetic, thermodynamic, and dielectric properties

M. Gen; H. Ishikawa; A. Miyake; T. Yajima; H. O. Jeschke; H. Sagayama; A. Ikeda; Y. H. Matsuda; K. Kindo; M. Tokunaga; Y. Kohama; T. Kurumaji; Y. Tokunaga; T. Arima

doi:10.1103/physrevmaterials.7.104404

arXiv · 2303.10671

Breathing pyrochlore magnet CuGaCr$_{4}$S$_{8}$: Magnetic, thermodynamic, and dielectric properties

M. Gen·H. Ishikawa·A. Miyake·T. Yajima·H. O. Jeschke·H. Sagayama·A. Ikeda·Y. H. Matsuda·K. Kindo·M. Tokunaga·Y. Kohama·T. Kurumaji·Y. Tokunaga·T. Arima

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Abstract

We investigate the crystallographic and magnetic properties of a chromium-based thiospinel CuGaCr$_{4}$S$_{8}$. From a synchrotron x-ray diffraction experiment and structural refinement, Cu and Ga atoms are found to occupy the tetrahedral $A$-sites in an alternate way, yielding breathing pyrochlore Cr network. CuGaCr$_{4}$S$_{8}$ undergoes a magnetic transition associated with a structural distortion at 31 K in zero magnetic field, indicating that the spin-lattice coupling is responsible for relieving the geometrical frustration. When applying a pulsed high magnetic field, a sharp metamagnetic transition takes place at 40 T, followed by a 1/2-magnetization plateau up to 103 T. These phase transitions accompany dielectric anomalies, suggesting the presence of helical spin correlations in low-field phases. The density-functional-theory calculation reveals that CuGaCr$_{4}$S$_{8}$ is dominated by antiferromagnetic and ferromagnetic exchange couplings within small and large tetrahedra, respectively, in analogy with CuInCr$_{4}$S$_{8}$. We argue that $A$-site-ordered Cr thiospinels serve as an excellent platform to explore diverse magnetic phases along with pronounced magnetoelastic and magnetodielectric responses.

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M. Gen, H. Ishikawa, A. Miyake, T. Yajima, H. O. Jeschke, H. Sagayama, A. Ikeda, Y. H. Matsuda, K. Kindo, M. Tokunaga, Y. Kohama, T. Kurumaji, Y. Tokunaga, T. Arima. 2023-03-19. Breathing pyrochlore magnet CuGaCr$_{4}$S$_{8}$: Magnetic, thermodynamic, and dielectric properties. https://doi.org/10.1103/physrevmaterials.7.104404

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