Magnetocaloric effect in Ho-Er-Gd-Co multicomponent compounds.

We report magnetic and magnetocaloric properties of polycrystalline series of the (Ho0.9Er0.1)(1-x)GdxCo2 (x = 0.05, 0.1 and 0.15) solid solutions. These samples were synthesized using high purity rare earth metals and cobalt. X-ray diffraction patterns taken at room temperature reveal that all compounds have the C15 cubic Laves phase structure. Magnetization measurements were carried out using a vibration sample magnetometer with a step motor in fields up to 14 T using a Bitter-type magnet. Heat capacity measurements have been performed in the temperature range of 2-300 K without magnetic field and in a magnetic field of 1 and 2 T. The magnetocaloric effect has been estimated in terms of isothermal magnetic entropy change for all solid solutions in magnetic fields up to 3 T. The effect of increasing Gd amount in (Ho0.9Er0.1)(1-x)GdxCo2 on the magnetic and magnetocaloric properties will be discussed.