Absence of room temperature ferromagnetism in Fe stabilized ZrO2 nanostructures and effect of Fe doping on its structural, optical and luminescence properties

Abstract

Undoped and Fe doped ZrO2 nanostructures were synthesized using sol–gel method. The structural analysis revealed that the tetragonal phase of ZrO2 nanostructures can be stabilized at 700 °C by 10 at.% doping of Fe into ZrO2 matrix for particle size less than 10 nm. The value of optical band gap of Fe doped ZrO2 nanostructures is decreased with Fe doping. It could be due to many-body interaction between Zr and Fe. The presence of oxygen vacancies in the synthesized samples was confirmed by PL measurements. VSM measurements revealed the room temperature ferromagnetism (RTFM) in undoped ZrO2 nanostructures. However, the RTFM of the material goes off by Fe doping into ZrO2 matrix. The Fe doping induces magnetic transition from ferromagnetic to paramagnetic in Fe doped tetragonal ZrO2 nanostructures. The paramagnetic nature of Fe doped ZrO2 nanostructures is explained by density functional theory (DFT) employing breaking symmetry approach (BS). The theoretical results show that the antiferromagnetic interaction between Zr–Fe and Fe–Fe may be responsible for the paramagnetic nature of Fe doped ZrO2 nanostructures.