observed by Meiklejohn and Bean1 (cobalt particles in shells of antiferromagnetic cobalt oxide); both are inhomogeneous and the coexistence of a ferromagnetic and an antiferromagnetic phase gives rise to large exchange bias. This demonstration of tuning the composition of certain Heusler alloys to attain exceptionally high exchange bias fields indicates a route for designing rare-earth-free har...

We demonstrate structural and room temperature magnetic properties of Fe doped ZnO nanofibers (NFs) obtained by electrospinning followed by calcination. The observed NFs, formed from crystalographically oriented, approximately 4.5 nm particles conglomerates, were approximately 200 nm in diameter. The reported synthesis of room temperature ferromagnetic Fe doped ZnO NFs is both facile and econom...

We show that a foliation of equilibria (a continuous family of equilibria whose graph covers all the configuration space) in ferromagnetic models are ground states. The result we prove is very general, and it applies to models with long range interactions and many body. As an application, we consider several models of networks of interacting particles including models of Frenkel-Kontorova type ...

The orthogonal relation between the magnetic aspect (spin) of scatterable elementary particles’ energy with respect to their direction of motion can be demonstrated at the macroscopic level by mechanical means. It can be proven that force aligning the spins of unpaired electrons in ferromagnetic materials causes the unidirectional carrying energy of the electrons involved to align orthogonally ...

Cold-pressed powders of the half-metallic ferromagnet CrO2 are dielectric granular metals. Hysteretic magnetoresistance with maxima at the coercive field arises from interparticle contacts. Dilution with insulating antiferromagnetic Cr2O3 powder reduces the conductivity by 3 orders of magnitude, but enhances the magnetoresistance ratio which reaches 50% at 5K. The negative magnetoresistance is ...

Last years several experiments were performed, which studied the Bose-Einstein condensation of quasi-particles, in particular, magnons in magnetically ordered systems. Recently the Bose-Einstein condensation of magnons was observed at room temperatures in a ferromagnetic film. The theory of the condensation (re-distribution) of magnons under the conditions of pumping, which explains many featur...

The synthesis and magnetic properties of Ni nanoparticles containing <150 atoms are described. These materials are prepared in an organic solvent using hydrophobic dendrimers as templates, which results in a high degree of size monodispersity. The dendrimer-encapsulated nanoparticles were characterized by UV-vis spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy....

INTRODUCTION Clinical MRI scanners can provide large amounts of electromagnetic energy that potentially could be used for actuation as well as imaging and so provide a complete environment for robotic interventions. The idea of using MR scanner magnetic gradients for actuating and tracking millimeter or micrometer size ferromagnetic particles was initially proposed and performed by Martel et al...

A polymer gel (ferrogel) is an assembly of ferromagnetic nanoparticles embeded in gel. In the ferrogel, the finely distributed magnetic particles are suspended in the swelling liquid and forma flexible matrix due to adhesive forces. The present paper describes an electric and acoustic study of magnetic field sensitive poly (dimethyl siloxane) ferrogel. The results showed hysteresis of acoustic ...

We study numerically the ground state magnetization for clusters of interacting electrons in two dimensions in the regime where the single particle wave functions are localized by disorder. It is found that the Coulomb interaction leads to a spontaneous ground state magnetization. For a constant electronic density, the total spin increases linearly with the number of particles, suggesting a fer...