Varying critical behaviour of stacked triangular lattice Ising antiferromagnets in the presence of spin-lattice coupling

We perform Monte Carlo simulations on the multilayered triangular-lattice Ising antiferromagnet with six sublattices in the frustrated abab stacking and quantify the impact of spin-lattice coupling on its critical properties in the vicinity of the antiferromagnetic phase transition. By invoking the Einstein site spin-phonon model and by varying the strengths of both antiferromagnetic interlayer exchange interactions and spin-lattice coupling, we compute various thermodynamic observable that characterize how the geometrical frustration and the spin-phonon coupling affect the critical behaviour of the system. Using finite-size scaling, we determine the nature of phase transition and the critical exponents, the latter being found to vary with varying strength of couplings. We find that the transition temperature is more sensitive to the interlayer coupling strength rather than that of magnetoelastic coupling. The variation of critical exponents with the strength of spin-lattice coupling hints to the importance of magnetoelastic interaction in the vicinity of magnetic phase transition in strongly correlated magnetic systems, as already observed in several experiments.