2005/09/15 by K. Sheshadri, Sheshadri, K., A. Chainani +1
Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.cond-mat/0509392
11 pages, 3 figures
arxiv created 2005/09/19 · arxiv updated 2009/12/01
Based on experimental observations in AxMO2 (A = Na, Li; M = Co, Ni), a model for suppression of magnetic frustration by electron doping in a nearest-neighbour antiferromagnetic triangular lattice is presented. It is found that frustration can be quantified, as determined by geometry and bond-counting, and its magnitude is a non-monotonic function of x. A mean-field calculation provides temperature-dependent magnetization, spin-entropy and heat capacity. Low-doping (x = 0.25, 0.33) results in a highly frustrated regime. A0.5MO2 has strongest order and no frustration, while high doping (x = 0.67, 0.75) leads to low frustration and higher spin-entropy. The results agree with experiments including neutron scattering, spin entropy-driven thermoelectricity and ion ordering.