Stage-2 MnCl2 GIC magnetically behaves like a quasi 2D XY antiferromagnet on the triangular lattice with the spin freezing temperature TSG (= 1.1 K). We have undertaken an extensive study on the T dependence of specific heat in the absence of an external field H and in the presence of H along the c-plane. The magnetic specific heat Cmag at H = 0 shows no anomaly at TSG, but exhibits double broad peaks around 5 and 41 K. The anomaly at 41K is the onset of short range spin correlation. The magnetic specific heat C mag at H = 0 is described by Cmag / α(1/T 2) exp(- ΔT ) with Δ = 1.41 ± 0.03 K, while C mag at H = 10 kOe is proportional to T. The entropy due to the broad peak around 5K is 1/3 of the total entropy. The residual entropy is 63% of the total entropy because of highly frustrated nature of the system. These results are consistent with the previous DC susceptibility, neutron scattering, and electron spin resonance (ESR) experiments.
ASJC Scopus subject areas
- Physics and Astronomy(all)