Effect of progressive substitution of spin-3/2 by spin-7/2 on the magnetocaloric properties of a mixed spin binary alloy system: A Monte Carlo study

Using Monte Carlo simulation the concentration dependency of the cooling exponent ( n) of a binary alloy A _xB _{1- x} mixed spin system (7/2, 3/2) was studied rigorously. For low magnetic field ( h) the entropy change ( Δ S ) , excellently follows the relation Δ S ∝ h n . The exponent n hardly changes with x within the region 0.5 < x < 0.75. But for further increment of x > 0.75, n sharply drops down. The exponent n is strongly affected by the exchange interaction energy ( ε ) . Due to the decrement of the antiferromagnetic interactions n value rapidly decreases. For the increment of x or the number of A(spin-7/2) atom the magnetization M as well as the magnetic entropy change Δ S increases. The phase transition temperature (i.e. Curie temperature) t C linearly decreases for the increase of x.