Influence of La3+ site substitution on the structural, magnetic and magnetocaloric properties of ZnFe2-xLaxO4 (x=0.00, 0.001, 0.005 and 0.01) spinel zinc ferrites

ZnFe2O4 ferrite nanoparticles are arousing a great interest in the biomedical field, in particular for magnetic hyperthermia application, thanks to their beneficial physical and chemical properties. Here, we report the discovery of a magnetocaloric effect at low temperature in ZnFe2-xLaxO4 ferrite nanoparticles (<= 10 K). Indeed, sol-gel technique was employed to synthesize ZnFe2-xLaxO4 (x = 0.00, 0.001, 0.005 and 0.01) spinel. Structural, magnetic and magnetocaloric properties of ZnFe2-xLaxO4 spinel were investigated in detail. The XRD results show that the crystallite size was reduced with the increase in La s+ cations. Magnetic properties and magnetocaloric response of ZnFe2-xLaxO4 ferrite have been studied as a function of La3+ concentration. It was demonstrated that, Neel temperature (T N ) decreased slightly with the La3+ content. Furthermore, the magnetic moment decreased with the addition of La3+ cations. The peak of magnetic entropy change (-Delta S-M(max)) slowly decreased. Interestingly, a notable increase in the value of the relative cooling power (RCP) was observed with La3+ doping.