Gd2O3 nanoparticles prepared by spark discharge method: Structure and magnetocaloric properties

Several batches of nanoparticles of gadolinium oxide Gd2O3 were obtained by the electrophysical spark discharge (ESD) method using selected variations of the value of the energy supplied to the discharge gap. The change of the charge voltage led to a change in the energy supplied to the discharge gap in the range of 3 J to 55 J. The average size of spark discharge nanoparticles in all cases was close to 8 nm in accordance with low-temperature nitrogen adsorption data. Gd2O3 nanoparticles contained two crystalline phases (cubic and monoclinic), the amount of which varied within certain limits by changing the parameters of the spark discharge. The obtained maximum values of the magnetic entropy change Delta SM of the studied ESD Gd2O3 nanoparticles with a monoclinic phase content of less than 40 wt% are not inferior to the value of Delta SM of Gd2O3 nanoparticles obtained by chemical methods. The spark discharge technique seems to be a promising technology for manufacturing of gadolinium oxide nanoparticles applications for the magnetic cooling systems of cryogenic refrigeration.