Quantum effect in the antiferromagnetic layered-perovskite materials with the triangular-lattice

Due to the exotic quantum phenomena of the frustrated quantum magnets, investigating the related ground states has caught a lot of attention. The two-dimensional Spin-1/2 triangular-lattice antiferromagnet (TLAF) is a typical example: the quantum fluctuations could interfere the spin states, such as the disordered liquid and glass phases, and keep them with the complicated interactions among the geometric frustration, low dimensionality, and small spin. Ba₃CoSb₂O₉ is the first spin-1/2 equilateral TLAF without the Dzyaloshinskii-Moriya interaction, and the magnetic Co²⁺ triangular layers are well separated by the non-magnetic clusters of the Sb₂O₉ bioctahedra and Ba²⁺ ions. The strong quantum effects were observed from a non-collinear 120° spin structure in zero magnetic field into a collinear up-up-down (uud) state in a finite range of applied magnetic field [1, 2]. Through the experimental and theoretical studies, we found that the Linear Spin-Wave + 1/S treatment was inadequate to explain our experimental observation and the interlayer interaction could not be ignored in the system [3, 4]. In order to study the interlayer interactions and magnetic moments dependence on the quantum effect, the work has been extended to the other TLAFs of the multi-layered perovskite compounds with S=1 and 5/2. Moreover, the non-magnetic B'-site ions of the A_mBB'_m-1O_3m were discussed.

References:
[1] Y. Shirata et al., Phys. Rev. Lett. 108, 057205 (2012).
[2] T. Susuki et al., Phys. Rev. Lett. 110, 267201 (2013).
[3] J. Ma et al., Phys. Rev. Lett. 116, 087201 (2016).
[4] Y. Kamiya et al., Nat. Comm. 9, 2666 (2018).