Effects of substitutional Fe and oxygen vacancies on room temperature ferromagnetism of Fe-doped In2O3 dilute magnetic nanowires

Abstract

The magnetic behavior and origin of dilute magnetic nanowires are critical for further development and application of nanoscale spintronic devices. In this work, the Fe doping into single-crystalline In 2 O 3 nanowires are fabricated using chemical vapor deposition (CVD) method to research these problems based on theoretical and experimental analysis. The XRD, XPS, TEM and XAS results show that the deposited Fe-doped In 2 O 3 nanowires possess the cubic bixbyite structure and the doped Fe ions substitute for the In sites of In 2 O 3 lattice with +2 and + 3 mixed valences. The PL results prove the existence of single ionized oxygen vacancies as well as the defect complexes of donor (oxygen vacancy)-acceptor (Fe impurity) pairs. The intrinsic room temperature ferromagnetism can be observed for the Fe-doped In 2 O 3 nanowires and the saturation magnetization largely enhance with Fe doping. The first principles calculations show that the introducing of oxygen vacancy defects can cause strong hybridization between Fe 3d and O 2p orbitals at the Fermi level, resulting in the transition from antiferromagnetic to ferromagnetic coupling between the Fe ions. These results open up the possibilities for exploring spin-electronic devices. • Effects of Fe doping on local structure, optical and magnetic properties of Fe-doped In 2 O 3 nanowires are studied. • The doped Fe ions substitute for the In sites of In 2 O 3 lattice with +2 and + 3 mixed valences. • Single ionized oxygen vacancies and the defect complexes of donor -acceptor pairs can be observed. • Introducing of oxygen vacancies results in the transition from antiferromagnetic to ferromagnetic coupling between Fe ions.