Speaker
Description
Application of external pressure, hydrostatic or uniaxial, is an appropriate way to change (tune) the properties of quantum magnets with geometrical frustration as it can modify the distances between atoms or layers, or change the angles in frustrated triangles [1-3]. In this contribution we present the influence of hydrostatic and uniaxial pressure on the magnetically strongly anisotropic thulium tetraboride (TmB$_4$), which is a metallic model system of the frustrated Shastry-Sutherland lattice (SSL), one of the most important and most studied models of quantum magnetism. In case of uniaxial pressures, three various orientations of pressure vs. crystal axes of the sample vs. magnetic field were set. In the first case pressure $p$ was applied parallel to the $c$ easy axis of magnetization and the magnetic field $H$ (i.e. $p \parallel [001] \parallel H$). In the second one was pressure applied in direction [110] and parallel to magnetic field ($p \parallel [110] \parallel H$). In the third orientation pressure was applied in direction [110], perpendicular to field $H$ and sample $c$ axis (i.e. $p \parallel [110] \perp (c \parallel H)$). The obtained results show that while hydrostatic pressure leads mainly to an increase of ordering temperature $T_N$, uniaxial pressure leads to a reduction of the strong magnetic anisotropy. This anisotropy reduction is apparently associated with the disturbance of crystal field effects and destruction of the frustrated SSL geometry in TmB$_4$.
Acknowledgements
This work was supported by projects APVV-23-0226, VEGA 2/0034/24, DAAD-SAS-2023-02. Liquid nitrogen for experiments was sponsored by U.S. Steel Košice, s.r.o.
References
[1] S. Haravifard et al., “Crystallization of spin superlattices with pressure and field in the layered magnet SrCu2(BO3)2,” Nature Communications, vol. 7, no. 1. Springer Science and Business Media LLC, Jun. 20, 2016. https://doi.org/10.1038/ncomms11956
[2] S. Bettler et al., “Sign switching of dimer correlations in SrCu2(BO3)2 under hydrostatic pressure,“ Physical Review Research, vol. 2, no. 1. American Physical Society (APS), Jan. 10, 2020. https://doi.org/10.1103/physrevresearch.2.012010
[3] Z. Shi et al., “Discovery of quantum phases in the Shastry-Sutherland compound SrCu2(BO3)2 under extreme conditions of field and pressure,” Nature Communications, vol. 13, no. 1. Springer Science and Business Media LLC, Apr. 28, 2022. https://doi.org/10.1038/s41467-022-30036-w
