Shape-induced anisotropy in antiferromagnetic nanoparticles

Spatial detection of ferromagnetic wires using GMR sensor and based on shape induced anisotropy

The purpose of this paper is to introduce a new technique for row spacing measurement in a wire array using giant magnetoresistive (GMR) sensor. The self-rectifying property of the GMR-based probes leads to accurately detection of the magnetic field fluctuations caused by surface-breaking cracks in conductive materials, shape-induced magnetic anisotropy, etc. The ability to manufacture probes h...

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...

Dynamic rotor mode in antiferromagnetic nanoparticles