Gadolinium substitution effect on the thermomagnetic properties of Ni ferrite ferrofluids?,

PAULA BERCOFF; SILVIA JACOBO; MERCEDES ARANA

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016

0304-8853

This work is focused on the structural and magnetic characterization of Gd-doped Ni ferrite nanoparticlesand the preparation of a ferrofluid for applications in heat-transfer devices. For this purpose, spinelferrites NiFe2O4, and NiFe1.88Gd0.12O4 were prepared by the self-combustion method. The substitutedsample was obtained with a small amount of Gd inclusion and the excess appeared as GdFeO3. Thesmallest nanoparticles of both samples were properly coated and dispersed in kerosene. Thermal con-ductivities of the produced ferrofluids were measured at 25 °C under an applied magnetic field. There is asignificant enhancement in the thermal conductivity of the ferrofluid prepared with NiGd ferrite withrespect to the one with Ni ferrite, in presence of a magnetic field. This effect is directly related to thewell-known magnetocaloric effect of Gd.