1 research outputs found
Memory and aging effects in antiferromagnetic nanoparticles
We investigate slow dynamics of collection of a few noninteracting
antiferromagnetic NiO nanoparticles.
Our purpose is to enquire the role of size-dependent magnetization
fluctuations in temperature and time dependent properties of
antiferromagnetic nanoparticles. The zero-field cooled magnetization
exhibits size dependent fluctuations. We find memory effects in
field cooled magnetization, as well as aging effects in
thermoremenant magnetization of antiferromagnetic nanoparticles.
The antiferromagnetic nanoparticles show a stronger memory effect
than the corresponding effect in the ferromagnetic particles, when
the distribution of particles include very small sizes.
The situation reverses for bigger sizes. The relaxation of
the magnetization after a sudden cooling, heating and removal
of fields reiterate the memory effects. We also see a weak signature
of size-dependent magnetization fluctuations in aging effect of
antiferromagnetic nanoparticles. We find a two-step relaxation of
thermoremenant magnetization in antiferromagnetic case, which
differs qualitatively from relaxation of ferromagnetic nanoparticles