LAUSR

Abstract Polycrystalline Zn1-xCrxO (0.01 ≤ x ≤ 0.09) samples synthesised by solid state reaction technique were sintered at different temperatures following slow step sintering schedule, investigated for optical and magnetic properties using suitable characterisation techniques. Cr2O3 and CrO2 phases have been detected in the Raman spectra of Zn1-xCrxO samples with x ≥ 0.05. Photoluminescence study indicated improved optical property of the samples compared to undoped ZnO. While low percentage Cr doped samples show diamagnetic behaviour, different types of magnetic orderings are observed in the samples with higher percentage of dopants (x ≥ 0.05) for different sintering temperatures. The spin system and magnetic properties were analysed through Electron Spin Resonance study; g-value of 1.97 indicates Cr in 3+ valence state in ZnO. Presence of both Cr3+ and Cr4+ in ZnO understood to facilitate super exchange interactions to promote room temperature ferromagnetism. ESR study ensures improved magnetic homogeneity through slow step sintering process.