The ferromagnetic phase of an Ising model in d=3 , with any amount of quenched antiferromagnetic bond randomness, is shown to undergo a transition to a spin-glass phase under sufficient quenched bond dilution. This result, demonstrated here with the numerically exact global renormalization-group solution of a d=3 hierarchical lattice, is expected to hold true generally, for the cubic lattice an...

The theoretical description of the thermodynamic properties of ferromagnetic/superconductor/ferromagnetic (F/S/F) systems of nanoscopic scale is proposed. Their superconducting characteristics strongly depend on the mutual orientation of the ferromagnetic layers. In addition, depending on the transparency of S/F interfaces, the superconducting critical temperature can exhibit four different typ...

We have studied the ground-state phase diagram of a two-leg spin ladder with anisotropic ferromagnetic leg couplings under the influence of a symmetry-breaking transverse magnetic field by the exact diagonalization technique. In the case of antiferromagnetic coupling between legs we identified two phase transitions in the plane of magnetic field versus interchain coupling strength. The first co...

A model of the ferromagnetic origin of magnetic fields of neutron stars is considered. In this model, the magnetic phase transition occurs inside the core of neutron stars soon after formation. However, owing to the high electrical conductivity the core magnetic field is initially fully screened. We study how this magnetic field emerges for an outside observer. After some time, the induced fiel...

The current status and prospects of research on ferromagnetism in semiconductors are reviewed. The question of the origin of ferromagnetism in europium chalcogenides, chromium spinels and, particularly, in diluted magnetic semiconductors is addressed. The nature of electronic states derived from 3d of magnetic impurities is discussed in some detail. Results of a quantitative comparison between ...

Single phase Eu doped GdMnO3 ceramics were prepared using solid state reaction route. Several different characterization techniques were used to investigate the structural and magnetic properties of the samples, including X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and Vibrating Sample Magnetometer (VSM). All samples indicated single p...

We report here the first synthesis of mesoscopic, monodisperse particles which contain nanoscopic inclusions of ferromagnetic cobalt ferrites. These monodisperse ferromagnetic composite particles readily self-assemble into magnetically responsive photonic crystals that efficiently Bragg diffract incident light. Magnetic fields can be used to control the photonic crystal orientation and, thus, t...

The dynamic interplay of transport, electrostatic, and magnetic effects in the resonant tunneling through ferromagnetic quantum wells is theoretically investigated. It is shown that the carrier-mediated magnetic order in the ferromagnetic region not only induces, but also takes part in intrinsic, robust, and sustainable high-frequency current oscillations over a large window of nominally steady...