Structural, optical and magnetic properties of Cr3+ doped ZnO nanopowder

Cr3+ doped ZnO nanopowder has been synthesized by solid state reaction with the assistance of sonication. Structural, optical and magnetic properties have been studied by various techniques. X-ray diffraction measurements demonstrate that Cr-doped ZnO nanopowder has a wurtzite structure. Scanning electron microscope images show irregular shaped stone like structures. Optical absorption spectrum exhibits the characteristic bands of Cr3+ ions. Electron paramagnetic resonance spectrum exhibits a strong resonance signal at g = 1.986 due to exchange coupled Cr3+ ion pairs. From correlation spectrum and optical absorption data, the nature of bonding of Cr3+ ion with its ligands has been discussed. The room temperature Photoluminescence spectrum exhibites emission bands at 405, 436, 487 and 543 nm under an excitation of 365 nm. Commission International de I’Eclairage colour coordinates have been determined from the emission spectrum. Magnetometric measurements show that Cr-doped ZnO nanopowder exhibits ferromagnetism at room temperature.