Magnetocaloric effect in GdRu[sub 2]Ge[sub 2].

We have studied the magnetocaloric effect (MCE) in GdRu[sub 2]Ge[sub 2] by means of measurements of temperature and field dependence of the specific heat and the magnetization. Two anomalies were observed at T[sub 1=29K and T[sub 2]=32K in the zero-field specific-heat curve. Magnetization measurements showed that the magnetic moments of the Gd ions order antiferromagnetically below T[sub 2] and follow the Curie-Weiss Law above T[sub 2]. The magnetic measurements also showed that there exists a field-induced antiferromagnetic to ferromagnetic transition below T[sub 1]. The magnetocaloric properties estimated from the magnetization measurements by means of the thermodynamic Maxwell relation are in good agreement with those obtained from the specific-heat measurements. The largest observed adiabatic temperature change, Δ T[sub ad], is approximately 10 K for a field change from 0 to 15 T. The considerably large magnetic entropy change is due to the field-induced magnetic phase transition, which is magnetically reversible. [ABSTRACT FROM AUTHOR]