Experimental
GdCo2 was prepared by melting the pure constituents in stoichiometric amounts pressed in the form of a pellet of about 4 g in a high-frequency induction furnace on a water cooled tantalum hearth under an argon atmosphere. The sample was turned upside down and remelted several times then it was wrapped in a tantalum foil and then annealed in an evacuated silica tube for15 days at 1100°C.
XRD powder diffraction were performed in a Philips 1710 X-ray powder diffractometer using Cu K? radiation.
The electrochemical hydriding was performed in a three compartment cell using rotating disk electrode configuration. The cell was filled with 6M KOH aqueous solution. The sample rotation was fixed at 500 rpm and a cathodic current of 30mA for different period of time ranging between 1 to 20 hours was applied to the GdCo2 pellet.
DC magnetisation measurements were performed using an Oxford Maglab 2000 system operating in the 3 -380 K temperature range with applied .fields up to 5 T. A calibrated Cernox type thermometer from Lake Shore Cryotronics Inc.was used as temperature sensor.