Dynamic rotor mode in antiferromagnetic nanoparticles

Dynamic rotor mode in antiferromagnetic nanoparticles

Memory and aging effects in antiferromagnetic nanoparticles

We investigate the slow dynamics of polydisperse antiferromagnetic NiO nanoparticles using Monte Carlo simulations. The zero-field cooled and field cooled magnetizations exhibit the size-dependent fluctuations. We find memory effects and very weak aging effects in a noninteracting polydisperse assembly of nanoparticles. The relaxation measurements of magnetization after a sudden cooling, heatin...

Antiferromagnetic spin correlations in MnO nanoparticles

We have investigated nearly monodispersive MnO nanoparticles of 10 nm diameter by polarised neutron diffraction with XYZ-polarisation analysis. We found no long-range ordering down to 3.5K. A broad magnetic peak appeared close to Q1⁄4 (1/2,1/2,1/2) signifying short-range antiferromagnetic correlations. The correlation length was found to be about 2.4 nm at T1⁄43.5 K. The correlation length decr...

Thermoinduced magnetization in nanoparticles of antiferromagnetic materials.

We show that there is a thermoinduced contribution to the magnetic moment of nanoparticles of antiferromagnetic materials. It arises from thermal excitations of the uniform spin-precession mode, and it has the unusual property that its magnitude increases with increasing temperature. This has the consequence that antiferromagnetism is nonexistent in nanoparticles at finite temperatures and it e...

Remanent magnetization in CoO antiferromagnetic nanoparticles

We report a study on the remanent magnetization Mr induced by field cooling across the ordering temperature TN in antiferromagnetic CoO nanoparticles with different sizes. The nanoparticles are composed by a structurally and magnetically ordered core and a structurally ordered and magnetically disordered shell with a thickness of about 2 nm. The ordered core has cell parameters, moments directi...