We investigate the large-scale evolution of a relativistic magnetic reconnection in an electron–positron pair plasma by a relativistic two-fluid magnetohydrodynamic (MHD) code. We introduce an interspecies friction force as an effective resistivity to dissipate magnetic fields. We demonstrate that magnetic reconnection successfully occurs in our two-fluid system, and that it involves Petschek-t...

Theory of magnetoresistance in films of dilute magnetic alloys. Abstract Giordano measured the magnetoresistance of dilute magnetic alloys Au(Fe) films of different thickness. He explained the difference in the magnetic field saturation for different thickness by the magnetic surface anisotropy for the impurities has been suggested and evaluated earlier, which is due to spin-orbit scattering in...

We present the first numerical model of the magnetohydrodynamical cosmic-ray (CR) driven dynamo of the type proposed by Parker (1992). The driving force of the amplification process comes from CRs injected into the galactic disk in randomly distributed spherical regions representing supernova remnants. The underlying disk is differentially rotating. An explicit resistivity is responsible for th...

The magnetotransport and magnetic properties of chemically ordered ~001! L10 FePt epitaxial thin films with small scale perpendicularly magnetized stripe domains have been investigated. Film growth conditions are used to systematically vary the degree of chemical order, the magnetic anisotropy, and magnetic domain sizes. The longitudinal and transverse ~Hall! resistivities are correlated with b...

Magnetization and Hall resistivity have been investigated for single crystals of Dy-doped Nd2Mo2O7. A sharp decrease of the Hall resistivity upon a metamagnetic transition, perhaps associated with magnetic-field (H) induced flop of Dy moments, has been observed in the Dy-doped crystals only for H ‖ [111] direction. In addition, the sign of the Hall resistivity at a high field, both for H ‖ [100...

Magnetic granular solids consist of nanometer-sized magnetic particles uniformly dispersed and embedded in an immiscible insulating or metallic medium. They display a rich variety of magnetic properties and giant magneto-transport properties due to their unique nanostructure, which can be usefully described by the metal volume fraction and the metal particle diameter of granular solids. Fabrica...

The theory of large scale dynamos is reviewed with particular emphasis on the magnetic helicity constraint in the presence of closed and open boundaries. In the presence of closed or periodic boundaries, helical dynamos respond to the helicity constraint by developing small scale separation in the kinematic regime, and by showing long time scales in the nonlinear regime where the scale separati...

The magnetohydodynamic (MHD) kinematics model describes the electromagnetic behavior of an electrically conducting fluid when its hydrodynamic properties are assumed to be known. In particular, the MHD kinematics equations can be used to simulate the magnetic field induced by a given velocity field. While prescribing the velocity field leads to a simpler model than the fully coupled MHD system,...

We discuss high pressure resistivity results on mixed valent cerium and europium systems in which magnetic order plays an important role. In the CeMn2Si2-based systems the magnetic order is due to the manganese sublattice, and the cerium mixed valentfheavy fermion effects persist at least in the ~tife~om~etic~ly ordered phase of these systems. In the EuO system, the europium ferromagnetic order...

UPt orders ferromagnetically at ambient pressure at 28 K. Upon increasing pressure, an additional magnetic phase transition appears around 17 K. While the upper transition behaves with field as a typical paramagneticferromagnetic transition, the lower one exhibits antiferromagnetic behavior. With pressure both transitions shift towards lower temperatures. Around 1.5 GPa the upper magnetic trans...