SKM 2023 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 52: Frustrated Magnets: Strong Spin-Orbit Coupling
TT 52.7: Vortrag
Donnerstag, 30. März 2023, 16:45–17:00, HSZ 201
Thermal expansion and magnetostriction as the probe of exotic magnetism in honeycomb BaCo2(AsO4)2 — •Prashanta K. Mukharjee1, Bin Shen1, Anton Jesche1, Julian Kaiser1, Philipp Gegenwart1, and Alexander Tsirlin2 — 1Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany — 2Felix Bloch Institute for Solid-State Physics, University of Leipzig, 04103 Leipzig, Germany
The 3d7 Co-based honeycomb materials have received wide attention as a possible platform for the experimental realization of the celebrated Kitaev model. Here, we elucidate the thermodynamic properties of the candidate material BaCo2(AsO4)2 using high-resolution thermal expansion and magnetostriction measurements. At 2 K, with an increase in field, the linear magnetostriction coefficient shows two well-separated anomalies around critical field Hc1 ∼ 0.2 T and Hc2∼ 0.5 T transition around Hc1 is hysteretic, pointing towards a first-order type transition, whereas the transition at Hc2 lacks hysteresis, reflecting the second-order nature. The linear thermal expansion coefficient shows a sharp positive peak in 0 T, which decreases, then changes its sign with the rise in the field and smears out entirely above Hc2. Below TN, for Hc1 << H << Hc2, our angle-dependent magnetization shows an apparent six-fold symmetry, whereas significant deviations have been observed below Hc1 and above Hc2. We draw the in-plane phase diagram from the above experiments and other complementary techniques and discuss the interplay of first and second-order transitions in this material.