Influence of Ni doping on room temperature electrical and magnetic properties of WO3 synthesized by solid state route

Abstract

Tungsten trioxide (WO3) is a promising functional material

however, its limited magnetic response and tunable electronic properties restrict its broader application in advanced electronic and sensing devices. To address these limitations, the present study aims to investigate Ni-doped WO3 as a dilute magnetic semiconductor, focusing on the role of defect states and carrier dynamics in tailoring its multifunctional properties. For this, a series of W1-xNixO3(x?=?0�0.06) samples were synthesized via a conventional solid-state reaction route. X-ray diffraction analysis confirms the stabilization of the monoclinic WO3 phase, with a solubility limit of Ni up to x?[jls-end-space/]0.06. Increasing Ni incorporation leads to a pronounced decrease in both the average crystallite size and grain size. X-ray photoelectron spectroscopy analysis reveals that the concentration of oxygen vacancies (Vo[jls-end-space/]) systematically increases with increasing Ni dopant concentration. Raman analysis confirmed the retention of the monoclinic WO3 phase upon Ni incorporation, with no observable peak shift, indicating successful doping without structural distortion. Optical studies indicated a widening of the bandgap with increasing carrier concentration, consistent with the Burstein-Moss shift. Hall measurements indicate n-type conductivity with enhanced carrier concentration and reduced mobility, suggesting defect-mediated charge transport, which supported increase of(Formula presented). Dielectric analysis revealed an increase in both dielectric constant and loss, attributed to carrier hopping and the presence of Ni-O-W dipolar complexes. Electrical transport was dominated by frequency-dependent hopping conduction, with impedance analysis confirming reduced resistance at moderate doping. Magnetic measurements demonstrate weak room-temperature ferromagnetism, which is interpreted using the bound magnetic polaron model, where Vo act as localized centers facilitating magnetic coupling between Ni ions. Overall, Ni doping effectively modulates defect states, carrier concentration, dielectric response, and magnetic ordering in WO3. The strong correlation among Vo[jls-end-space/], charge carrier dynamics, and magnetism highlights W1-xNixO3 as a promising candidate with significant potential for applications in gas sensing, electronics and spintronic devices. � 2026 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/