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Ba8CoNb6O24: A Spin-1/2 Triangular-Lattice Heisenberg Antiferromagnet in the Two-Dimensional Limit



R. Rawl, L. Ge, H. Agrawal, Y. Kamiya, C. R. Dela Cruz, Nicholas Butch, X. F. Sun, M. Lee, E. S. Choi, J. Oitmaa, C. D. Batista, M. Mourigal, H. D. Zhou, J. Ma


The quasi-two-dimensional perovskite Ba8CoNb6O24 comprises equilateral effective spin-1/2 Co2+ triangular layers separated by six nonmagnetic Nb5+ layers. Susceptibility, specific heat and neutron scattering measurements combined with high-temperature series expansions and spin-wave calculations confirm that Ba8CoNb6O24 is basically a two-dimensional(2D)magnet with no detectable spin anisotropy and no long range magnetic ordering down to 0.06 K. In other words, Ba8CoNb6O24 is very close to be a realization of the paradigmatic S = 1/2 triangular Heisenberg model, which is not expected to exhibit symmetry breaking at finite temperature according to Mermin and Wagner theorem.
Physical Review B




Rawl, R. , Ge, L. , Agrawal, H. , Kamiya, Y. , Dela Cruz, C. , Butch, N. , Sun, X. , Lee, M. , Choi, E. , Oitmaa, J. , Batista, C. , Mourigal, M. , Zhou, H. and Ma, J. (2017), Ba<sub>8</sub>CoNb<sub>6</sub>O<sub>24</sub>: A Spin-1/2 Triangular-Lattice Heisenberg Antiferromagnet in the Two-Dimensional Limit, Physical Review B, [online], (Accessed February 28, 2024)
Created February 16, 2017, Updated October 12, 2021