Room Temperature Ferromagnetism and its "Switch" Behaviour in some Dilute Magnetic Oxides: an Electronic Structure and Magnetization Study

摘要: ZnO doped with a few per cent of magnetic ions such as Ni, Fe, Co exhibits room temperature ferromagnetism (RTFM), transforming it into very promising candidate for future spintronic applications. Two samples i.e. Ni and Cr (5% each) have been investigated in the present work. The were characterized by Rietveld refinement X-ray diffraction (XRD) patterns superconducting quantum interference device (SQUID) magnetometry. analysis confirms that both polycrystalline possess wurtzite structure no evidence any secondary phase. SQUID measurements exhibit diamagnetic state pristine paramagnetic as-synthesized (Cr Ni)-doped samples. However, post annealing H2 vacuum drive them to remarkable ferromagnetic at temperature. No element specific signature was seen. Then photoelectron spectroscopic (XPS) performed investigate their electronic exploring origin these diluted semiconductor materials. XPS results confirm creation oxygen vacancies upon Hydrogen/ annealing, owned (Ni/Cr) 3d¬−O 2p hybridization. findings suggest intrinsic ZnO. important feature this work is consequent property changes are found be reversible regard re-heating air, showing switch “on” “off” ordering matrix.