Dense inter-particle interaction mediated spontaneous exchange bias in NiO nanoparticles

Abstract

The observed spontaneous exchange bias in NiO nanoparticles is induced by the dense inter-particle interactions.

Role of cobalt cations in short range antiferromagnetic Co3O4 nanoparticles: a thermal treatment approach to affecting phonon and magnetic properties

“…In the last few years, the SEB effect has been observed in various systems from bulk, FM/AFM core/shell, and nanocomposite to a pure AFM nanostructure 56 . In our previous magnetic study of a NiO nanoparticles system 57 , we also observed that the SEB field decreases with the increase of particle size. Therefore, for a proper understanding of the hysteresis loop shift in Co 3 O 4 nanoparticles, a comprehensive magnetic study is needed.…”

Unidirectional anisotropy mediated giant memory effect in antiferromagnetic Cr2O3 nanorods

“…Such inter-coupling sets up unidirectional anisotropy at the interface; for a detailed description was discussed in our previous work. 23…”

“…Very recently, we have reported spontaneous EB (SEB) from AF oxide NPs during the rst eld of hysteresis loop measurement. 23 SEB in AF NPs is governed by the unidirectional anisotropy (UA) across frustrated surface spins and the uncompensated AF core mediated by interfacial strongly pinned spins. Such bare AF NPs exhibits eld-cooled (FC) memory effect strength of which varies with the concentration of point defects resulting in disappearance in big size particles.…”

Strong Pinned-Spin-Mediated Memory Effect in NiO Nanoparticles

“…The pronounced broad peak temperature that appears on the ZFC magnetization curve near 178 K is associated with the blocking temperature of superparamagnetic NiO nanoparticles. An irreversible temperature T irr  = 262 K and a freezing temperature T f  = 6 K were observed from the M ( T ) curves [9]. The T f is associated with collective freezing of uncompensated surface spins of NiO [8].…”

“…Many of the above applications are based on the magnetic properties of the nanostructures, which vary with the synthesis method [7, 8], interparticle interaction [9], vacancies [10], and nanoparticle size [11], and show a pronounced effect on the magnetic properties of NiO nanoparticles. NiO, which is antiferromagnetic in its bulk form, exhibits ferromagnetic behavior at the nanoscale due to nickel vacancy defects, with its net magnetic moment increasing monotonically with decreasing particle size [7, 8].…”