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arXiv · 2210.09725

Microscopic spin Hamiltonian for a dipolar-Heisenberg magnet LiGdF4 from EPR measurements

S. S. Sosin·A. F. Iafarova·I. V. Romanova·O. A. Morozov·S. L. Korableva·R. G. Batulin·M. Zhitomirsky·V. N. Glazkov
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Abstract

Low-temperature electron paramagnetic resonance measurements are performed on single crystals of LiY_{1-x}Gd_xF_4 with weak x=0.005 and moderate x=0.05 concentration of Gd ions. Modeling of the experimental spectra allows us to precisely determine microscopic parameters of the spin Hamiltonian of the parent LiGdF4 material, including the nearest-neighbor exchange constant. The obtained parameters are further tested by comparing a strongly anisotropic Curie-Weiss temperature obtained for LiGdF4 in our static magnetization measurements with theoretically computed values. We find a fine balance between principal magnetic interactions in LiGdF4, which results in a hidden magnetic frustration presumably leading to a delayed magnetic ordering and an enhanced magnetocaloric effect at low temperatures.

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S. S. Sosin, A. F. Iafarova, I. V. Romanova, O. A. Morozov, S. L. Korableva, R. G. Batulin, M. Zhitomirsky, V. N. Glazkov. 2022-10-18. Microscopic spin Hamiltonian for a dipolar-Heisenberg magnet LiGdF4 from EPR measurements. https://doi.org/10.1134/s0021364022602299

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