A novel low temperature dynamic correlated paramagnet on a randomly diluted lattice

The presence of interacting spins on a lattice could lead to magnetically ordered states. However, magnetic frustration arising from competing exchange interactions could lead to such orderings being strongly suppressed, leading to quantum spin liquid-like states. An alternate approach to realize such exotic ground states is to introduce sufficient magnetic disorder in the lattice. Combining the two approaches, we explore a frustrated triangular lattice in presence of an extensive disorder such that the possibility of both spin liquid and spin glass states exist. Y2CuTiO6 has magnetically coupled spin- ½ Cu2+ on a triangular lattice in which 50% of the sites are randomly replaced by nonmagnetic Ti4+ atoms. We establish [1] that this system does not achieve either a magnetic ordering or a pure glassy state down to 50 mK, though the magnetic interaction strength is nearly 3000 times larger than this temperature. Various experiments and specific scaling behaviours of thermodynamic properties with temperature and magnetic fields suggest that the system remains in a disorder driven, dynamic cooperative paramagnetic state, opening new possibilities to explore the field of frustrated magnetism aided by disorder.

[1] S. Kundu, A. Hossain et al., Phys. Rev. Lett. 125, 117206 (2020)