Probing orbital magnetism of a kagome metal CsVSb by a tuning fork resonator.

The recently discovered kagome metal CsVSb exhibits a complex phase diagram that encompasses frustrated magnetism, topological charge density wave (CDW), and superconductivity. One CDW state that breaks time-reversal symmetry was proposed in this compound, while the exact nature of the putative magnetic state remains elusive. To examine the thermodynamic state of CsVSb and assess the character of the associated magnetism, we conducted tuning fork resonator measurements of magnetotropic susceptibility over a broad range of angles, magnetic fields, and temperatures. We found a cascade of phase transitions in the CDW phase. Of particular interest is a highly anisotropic magnetic structure that arises below about 30 K, with a magnetic moment along the c-axis that has an extremely small magnitude. This magnetic state demonstrates extremely slow dynamics and small saturate field, all suggest that electronic phase below 30 K breaks time reversal symmetry and has an unconventional origin.