d0 ferromagnetism in Li‐doped ZnO compounds
Résumé
Recently, d0 ferromagnetic oxide materials have been demonstrated as one of the promising materials for spintronics devices. Herein, we have studied the crystal structure, micro-structure, and magnetic properties of Li-doped ZnO, i.e., Zn1-xLixO (x = 0, 0.02, 0.04, and 0.06) compounds, prepared by the solid-state reaction route method. These compounds were found to crystallize in single phase of the hexagonal wurtzite structure with average crystallite size of 35–50 nm, as confirmed from the XRD patterns. The incorporation of Li in ZnO leads to decrease in the lattice parameters and cell volume. The SEM images reveal uniform sample morphology with average grains size of the order of 50–70 nm. The measurements of magnetic properties show that the un-doped ZnO exhibits diamagnetic behavior, whereas Li-doping in ZnO induces room-temperature ferromagnetism along with ultra-soft coercivity (~ 50 Oe), and with a maximum saturation magnetization of 0.10 emu/gm for x = 0.02 sample. The magnetic irreversibility behavior between zero-field-cooled and field-cooled magnetization vs. temperature data indicates the co-existence of spin-glass phase in all Li-doped compounds.
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