Crystallographic, magnetic and magnetocaloric properties in Yb-based alloy

•The magnetocaloric effect (MCE) of the polycrystalline alloy.•A ferromagnetic state.•An asymmetric shape of the −ΔSM dependence due to the presence of spin fluctuations.•A heavy fermion behavoiur.•−ln T dependence. The crystallographic and magnetic properties as well as the magnetocaloric effect (MCE) of the polycrystalline Yb0.5Gd0.5Ni5 alloy were investigated. The alloy crystallizes in the hexagonal CaCu5 structure. The magnetic properties showed the transition to a ferromagnetic state at Tc = 21.8 K. The heat capacity confirmed such behaviour. The Sommerfeld coefficient yielded a heavy-fermion value 790 mJ/mol.K2. Moreover, a −ln T dependence below 3 K at zero applied magnetic field was observed. The magnetocaloric effect shows an asymmetric shape of the −ΔSM dependence due to the presence of spin fluctuations.