Metamagnetoelectric transitions-enhanced multicaloric effect in multiferroics A2Cu2Mo3O12 (A=Rb and Cs) quantum spin chain

Abstract

The multicaloric properties of multiferroic A 2 Cu 2 Mo 3 O 12 (A = Rb and Cs) compounds are theoretically investigated through a frustrated one-dimensional spin ribbon chain of CuO 2 . The system submitted to external magnetic and electric field constraints grants the particular interest of metamagnetoelectric effect arising at relatively low temperatures. The isentropes of Rb 2 Cu 2 Mo 3 O 12 and Cs 2 Cu 2 Mo 3 O 12 exhibit about four major sharper dips by lowering temperature. This highlights four meta-transitions points which in turn are simultaneously metamagnetic and metaelectric, and therefore conveniently treated as metamagnetoelectric transitions. In the vicinities of the metamagnetoelectric transitions and in the quantum critical region, the thermal entropies are relatively large, which thus results in metamagnetoelectric transitions-enhanced multicaloric effect. Furthermore, this enhancement appears in the cooling process where the adiabatic magnetic and electric cooling rates diverge in the vicinity of the metamagnetoelectric transition points indicating the prominent low-temperature multicaloric effect. It is then certain that by making use of such large magnetoelectric coupling at metamagnetoelectric transition regions, the refrigerating efficiency of multiferroic materials will be further improved. • The multicaloric properties of multiferroic A 2 Cu 2 Mo 3 O 12 (A = Rb and Cs) compounds are theoretically investigated. • The system submitted to external magnetic and electric field constraints exhibits the metamagnetoelectric effect. • The metamagnetoelectric transitions increase the thermal entropy, leading to an enhancement of the multicaloric effect. • The adiabatic cooling rates at the metamagnetoelectric transitions emphasize prominent low-temperature multicaloric effect.