Chapter 23 - Nanocrystalline NiO powder: Synthesis, characterization and emerging applications

Abstract

Nanocrystalline NiO powders (crystallite size in range of 10–38nm) were fabricated by using the planetary grinding method from pure (commercial) NiO powder. Maximum moment of 1.08emu/g was achieved when milling at 30h. Linear behavior of exchange bias was observed with a decrease in NiO particle size. Low-temperature M-T measurement showed two peaks corresponding to the freezing of surface spin (due to size dependent) and spin-glass phase, which yielded the anisotropy property and enhanced the exchange bias under field-cool. EPR study revealed a close correlation between the structural and the induced magnetic properties. In addition, surface spin of NiO nanocrystals was higher than the spin at their core. Hence, the interaction between surfaces and particle core could lead to increase the lattice constant. This fabricated nanocrystalline NiO powder is the promising candidate for applications in storage device, sensor, and spintronic device. Moreover, the emerging applications such as environmental remediation, catalytic and biomedical applications are discussed herewith, which will be beneficial for the researchers.