Preparation and magnetic-optical properties of metastable Ni2+ doped rhombohedral indium oxide nanorods

Abstract

Ni²⁺ doped indium oxide is an important dilute magnetic semiconductor in spintronic device fields. In this paper, Ni²⁺ doped rhombohedral corundum-type indium oxide nanorods were prepared by simply annealing Ni²⁺ doped indium hydroxide precursors. The influences of doped concentrations and annealing temperatures on their crystalline structures, microscopic morphologies and macroscopic magnetic-optical properties were systematically investigated. We found that Ni²⁺ ions could induce the directional growth of doped indium oxide along (110) crystalline planes and change their infrared absorption, photoluminescence and magnetic properties. The magnetic transitions from diamagnetism to ferromagnetism and then to paramagnetism arose with increasing Ni²⁺ doped concentrations while a series of new infrared absorption peaks appeared and the photoluminescence properties were weakened since the doping of Ni²⁺ ions tuned the energy band structures of rhombohedral indium oxide host matrices.