Room-temperature ferromagnetism in Ni-doped TiO 2 diluted magnetic semiconductor thin films

Abstract

We report undoped and Ni-doped TiO 2 (x Ni = 0.00, 0.50, 1.00, 1.50, 2.00 and 2.50 wt.%) thin films fabricated on glass substrates by using a combination of solid-state reaction and dip coating techniques. The structural properties are observed by X-ray diffraction (XRD), which have depicted that annealing at 650 • C results in rutile Ni-doped TiO 2 as a major phase along with a minor anatase phase. The surface morphology of the deposited thin films, as measured by scanning electron microscopy (SEM), indicates granular spherical shaped nanostructures. Room-temperature ferromagnetism (RTFM) has been illustrated by all the grown thin films, as elucidated by vibrating sample magnetometer (VSM). Although Ni content has no pronounced effect on the crystallinity that indicates a substitutional replacement of Ni in TiO 2 lattice, however, Ni content is observed to influence the ferromagnetic behavior. Therefore, the present study signifies the potential spintronic applications of Ni-doped TiO 2 diluted magnetic semiconductors, fabricated by a low-cost method, as it exhibits RTFM with nanograins at the surface.

Structural, optical, and magnetic study of Ni-doped TiO2 nanoparticles synthesized by sol–gel method

“…6. The obtained curves revealed that the samples exhibited ferromagnetic behavior [46]. The graphs show typical hysteresis loops due to each specimen exhibiting coercivity and remanence (Fig.…”

Ab Initio Prediction of the Redox Potentials of 3d Transition Metals Embedded in a Semiconducting Host Lattice

“…Many experimental studies have reported on the synthesis and the characterization of 3d TM-doped rutile TiO 2 materials. ,,,,− ,,,− Figure b sums up the domain limits of cationic species in this specific host material as proposed by Mizushima et al − , based on experimental ( e.g. , photocurrent) and theoretical (semi-empirical model supported by photoconductivity and photo-ESR measurements) considerations.…”

“…These intentionally introduced point defects are well-known to create local structural distortions and in-gap electronic states, − which may significantly modify the electronic, magnetic, and/or optical properties of host materials. In the case of the TiO 2 compound, the introduction of TM dopants has been reported to enhance photocatalytic, − electrocatalytic, , or ferromagnetic − properties but also to alter the irreversible anatase-to-rutile phase transition …”

Nickel and sulfur codoped TiO2 nanoparticles for efficient visible light photocatalytic activity

“…It is well known that Ni ion is a more efficient dopant for TiO 2 , as it can improve electrical and magnetic properties. The reason for this enhancement has been tentatively ascribed to the suppression of electron-hole pair recombination on the surface of the TiO 2 catalyst by low valence Ni 2+ ions [34]. This upgraded activity was recognized as the enhanced separation of photo-generated electron-hole pairs due to the presence of Ni 2+ ions in TiO 2 [35].…”