Observation of ferromagnetic ordering in Ni-doped AlN polycrystalline powders

Ni-doped AlN polycrystalline powders were synthesized by solid-state reactions (SSRs). Raman spectra show that the A1 (TO) and E2 (high) peaks of the doped AlN samples are slightly red-shift compared with those of undoped AlN. All the doped samples show ferromagnetism at 150 K, whereas only the doped samples with higher Ni concentrations show ferromagnetism at 300 K. Broad emission bands between 280 nm and 450 nm in the photoluminescence spectra of the doped samples are intensified compared with that of undoped AlN. Our results confirm that room temperature ferromagnetism can be realized in the Ni-doped AlN polycrystalline powder samples.