Structures and magnetic properties of (Fe, Li)-codoped NiO thin films

Abstract

Rock-salt structured single-phase Ni0.98Fe0.02O and Ni0.93Fe0.02Li0.05O thin films with room temperature ferromagnetism were grown by pulsed laser deposition. It is found that the Li codoping into Ni0.98Fe0.02O significantly increases the saturation magnetic moment by a factor of 2, i.e., from 0.32μB∕Fe rising to 0.67μB∕Fe. The x-ray absorption fine structure spectral analyses at Fe and O K edge reveal that in both samples, the impurities are substitutionally incorporated into the NiO host. The first-principles calculations show that substitutionally doping Li ions into NiO leads to a strong hybridization between the Fe 3d states and the spin-split acceptor band at the Fermi level. As a result, the Fe 3d electron configuration is altered and the effective magnetic moment per Fe ion is enhanced.

Evolution of Structure, Microstructure, Electrical and Magnetic Properties of Nickel Oxide (NiO) with Transition Metal ion Doping

“…Since holes are generated on Li doping in NiO, the density of holes increases with increasing Li concentration. More hole carriers are expected to enhance the ferromagnetic coupling interaction between the hole carriers and the Fe 3d spins, thus making ferromagnetic coupling interaction more effective as was reported for Fe, Li co-doped thin films [29,59]. Similar phenomena have also been observed in the Li, Co co-doped ZnO and Cu, Fe co-doped ZnO thin films [60,61].…”

“…The evolution of magnetic ordering in the Fe, Li co-doped NiO showed an opposite behaviour in polycrystalline powder samples than in thin films with increasing Li concentration. The powder Ni 0.98-x Fe 0.02 Li x O samples [37] did not show the enhanced ferromagnetic properties unlike the Ni 0.98-x Fe 0.02 Li x O thin films [29,59].…”

“…In case of Fe, Li co-doped NiO thin films, the room temperature ferromagnetic ordering was shown to improve with increasing Li concentration [59]. Since holes are generated on Li doping in NiO, the density of holes increases with increasing Li concentration.…”

Ferromagnetic Behaviors in Fe‐Doped NiO Nanofibers Synthesized by Electrospinning Method

“…e low-symmetry structure will affect their peculiar magnetic properties [9]. In the recent study of DMS materials, nanoparticles, �lms structure of NiO have already been prepared by sol-gel techniques, hydrothermal route, and Pulsed lase deposition [10][11][12]. Unfortunately, the investigation of the Fe-doping effect on ferromagnetism of one-dimensional DMS �bers is very limited.…”

The film thickness effect on the physical properties of NiO thin films elaborated by Sol-gel method

“…Nanocrystalline NiO thin films can be produced by several techniques such as reactive evaporation, molecular beam epitaxy (MBE), magnetron sputtering technique, pulsed laser deposition (PLD), spray pyrolysis, sol-gel process, chemical vapor deposition, and electrochemical deposition [7][8][9]. NiO has been intensively studied as a promising material for gas sensors because of its wide band gap (3.6-4.0 eV) and high stability that are similar to ZnO [10,11].…”