Effect of zinc on structure, optical and magnetic properties and magnetic heating efficiency of Mn1-xZnxFe2O4 nanoparticles

Mn1-xZnxFe2O4 (0 <= x <= 0.7) nanoparticles were synthesised by a hydrothermal process. X-ray diffraction patterns reveal that all samples have spinel crystalline structures. Scanning electron microscopy and X-ray diffraction patterns show that nanoparticles are near-spherical in morphology and their average size is 13-45 nm. The elemental analysis was carried out by energy dispersive X-ray analysis technique. The optical direct band gap of Mn1-xZnxFe2O4 nanoparticle decreases from 2.38 to 1.88 eV as the Zn content increases. Moreover, the saturation magnetisation at room temperature tends to decrease with increasing Zn content. The specific absorption rate (SAR) values were measured at a fixed frequency of 178 kHz with magnetic field amplitude of 80 Oe. The SAR initially decreases with the sample concentration and its decrease is attributed to the enhancement of dipolar interaction and agglomeration of the particles. The intrinsic loss power (ILP) value varies between 6.5 and 15 nHm(2)kg(-1) in the biologically safe experimental limit of 1.13 x 10(9)Am(-1)s(-1). The high value of ILP makes these nanoparticles possible for potential candidates for treating magnetic hyperthermia.