SUPERPARAMAGNETIC-PARAMAGNETIC TRANSITION IN SMALL PARTICLES

Decoherence effects on the tunneling rate of paramagnetic and superparamagnetic particles

We analyze the effects of the environment on the spin tunneling process of paramagnetic and superparamagnetic particles and conclude that the “bare” macroscopic tunneling rate is hardly affected in such case, but others more effective processes come up to change the magnetization state of the particle. We measure the degree of coherence loss by the linear entropy which will account for all corr...

Multifunctional superparamagnetic Janus particles.

In this study, we report the microfluidic-based synthesis of a multifunctional Janus hydrogel particle with anisotropic superparamagnetic properties and chemical composition for the bottom-up assembly of hydrogel superstructures. In a uniform magnetic field, the resulting Janus magnetic particles fabricated in the present method exhibit chainlike or meshlike superstructure forms, the complexity...

Surface Effects in Superparamagnetic Magnetite Particles∗

We have studied the properties of unshielded and shielded (hybrid) nanosized spherical magnetite particles with diameter 10 ± 2 nm, which are superparamagnetic at room temperature, through magnetometry, X-ray powder diffraction, magnetic force microscopy imaging and Mössbauer spectroscopy. The unshielded material was prepared by co-precipitation either in air or in inert atmosphere and part of ...

Magneto-induced stress enhancing effect in a colloidal suspension of paramagnetic and superparamagnetic particles dispersed in a ferrofluid medium.

The magneto-induced stress and relative microstructure in a colloidal suspension of paramagnetic and superparamagnetic particles dispersed in a ferrofluid medium is studied using particle-level dynamics simulation. It shows that the stress perpendicular to the direction of an external uniaxial magnetic field can be strongly enhanced by increasing the ratio of paramagnetic particles to approachi...

Superparamagnetic relaxation of weakly interacting particles.