Electron spin resonance measurements of spin liquid candidate TbInO3 with superconducting resonators

TbInO3 is purported to host a quantum spin liquid ground state arising from frustrated anti-ferromagnetic spins lying on a triangular lattice. The magnetic exchange interactions between the Tb moments and the frustration from being on a triangular lattice prevent long-range ordering down to temperatures well below the interaction strength. Spin susceptibility measurements on bulk crystals have measured fluctuating spins down to 100 mK. However, the nature of the magnetic ground state of TbInO3 grown in thin-film form is unknown. In this work, we study thin films of TbInO3 epitaxially grown on yttria stabilized zirconia (YSZ) substrates.

To probe the Tb moments, we make use of microfabricated superconducting resonators designed to concentrate a microwave-frequency magnetic field in a micron-scale region. These resonators are well-suited for probing spin excitations in thin films containing magnetic moments, while being insensitive to dilute spins present in bulk substrates such as YSZ. We place TbInO3/YSZ films on top of the resonators in a flip-chip geometry. We report the dependence of resonator dissipation rate as a function of an in-plane magnetic field up to 0.5 T and temperature from 25 mK to 1 K.