Observation of room temperature ferromagnetism in transition metal ions substituted p-type transparent conducting oxide Cr2O3 thin films

In this report, we have performed comparative studies of the structural, optical, electrical, and magnetic behavior of pristine chromium oxide (PCO) and nickel (NCO), manganese (MCO), and cobalt (CCO) substituted Cr2O3 thin films. All thin films were epitaxially grown using the pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) pattern confirmed the single rhombohedral phase of Cr2O3. XPS analysis confirmed the successful incorporation of Ni, Mn, and Co atoms into the Cr2O3 thin films with mixed valence states. The UV-Vis spectra illustrated the optical transparency of 65-72% in the visible region for all thin films. Electrical measurement confirmed the improvement in electrical conductivity of Cr2O3 thin films with substitution of transition metal (TM) ions. The temperature-dependent magnetization depicted ferromagnetic order. On the other hand, a field -dependent study at 5 K exhibits enhanced magnetization due to the carriers-mediated bound magnetic polarons.