Magnetocaloric effect in (TbcR1-c)Co2(TbcR1-c)Co2 (R=ErR=Er and Ho)

•Microscopical description of the chemical disorder in rare earth based compounds.•Magnetocaloric effect in compounds with first order phase transition.•Effect of impurities on the nature of the magnetic phase transition.

In this paper we theoretically discuss the magnetocaloric effect in (TbcR1-c)Co2(TbcR1-c)Co2 (R = Er and Ho). To this end, we use a model Hamiltonian in which are included the 4f4f electrons from rare earth ions and the 3d3d electrons from Co ions. In the model is also included an extra term to account for the crystal electric field, which plays an important role in the magnetic and caloric properties of these compounds.