Magnetic properties of the quasi two-dimensional centered honeycomb antiferromagnet GdInO₃

The crystal structure and magnetic property of the single crystalline hexagonal rare-earth indium oxides GdInO3 have been studied by combing experiments and model calculations. The two inequivalent Gd³⁺ ions form the centered honeycomb lattice, which consists of honeycomb and triangular sublattices. The dc magnetic susceptibility and specific heat measurements suggest two antiferromagnetic phase transitions at T_N1=2.3K and T_N2=1.02K. An inflection point is observed in the isothermal magnetization curve, which can be an indication of an up-up-down phase with a 1/3 magnetization plateau, further supported by our theoretical calculation. We also observe a large magnetic entropy change originated from the magnetic frustration in GdInO₃. By considering a classical spin Hamiltonian, we establish the ground state phase diagram, which suggests that GdInO₃ has a weak easy-axis anisotropy and is close to the equilateral triangular-lattice system. The theoretical ground-state phase diagram may be used as a reference in NMR, ESR, or μSR experiments in future. © 2021 American Physical Society.