Thin ferromagnetic nanodisk in transverse magnetic field

The magnetization of a ferromagnetic nanodisk is studied using micromagnetic modeling. It is demonstrated that, under an external magnetic field applied perpendicular to the disk surface, magnetic phase transitions can occur between uniform states, between uniform and vortex states, and between vortex states with different directions of polarization. A simple variation model is proposed describing the observed magnetic states quantitatively.     

Breakdown magnetic field in an inductively coupled plasma

The Paschen curve shows that the breakdown voltage over a gap is a non-linear function of the product of the gas pressure and the gap distance for plasmas which are generated inside an electric field driven source. The Paschen breakdown relationship does not depend on the applied frequency and covers secondary emission at the electrodes of the discharge. Adapting the Paschen curve, a breakdown curve for a time-dependent magnetic field, typical for inductively coupled plasmas which sources are without electrodes, is examined here. It is shown that in this case the magnetic field breakdown curve does depend on the applied frequency.     

RF discharge in the transverse magnetic field numerical model

A numerical model of RF discharges in a steady transverse magnetic field is developed. This model is valid in a range of parameters (gas pressure, magnetic field, RF voltage) used in a number of experimental and technical installations. The comparison between numerical calculations and some experimental results is presented     

One-dimensional anisotropic Heisenberg model in the transverse magnetic field

The one-dimensional spin-1/2 XXZ model in a transverse magnetic field is studied. It is shown that the field induces a gap in the spectrum of the model with the easy-plane anisotropy. Using conformal invariance, the field dependence of the gap is found at small fields. The ground state phase diagram is obtained. It contains four phases with the long-range order of different types and a disordered phase. These phases are separated by critical lines, where the gap and the long-range order vanish. Using scaling estimates, the mean-field approach, and numerical calculations in the vicinity of all critical lines, we find the critical exponents of the gap and the long-range order. It is shown that the transition line between the ordered and disordered phases belongs to the universality class of the transverse Ising model.     

Ultrasonic attenuation of aluminium in transverse magnetic field

The attenuation of longitudinal sound wave in Al single crystal in high transverse magnetic field has been calculated by 4-OPW approximation. The wave vector of the sound wave is parallel to [1$\text{1}$0] axis. In general, the result agrees well with Berre's experiment. The attenuation plotted against the magnetic field direction has 3 peaks which are explained in terms of the geometry of the Fermi surface of Al.     

Suppression of magnetic relaxation by a transverse alternating magnetic field

The evolution of the spatial distribution of the magnetic induction in a superconductor after the action of the alternating magnetic field perpendicular to the trapped magnetic flux has been analyzed. The observed stabilization of the magnetic induction profile is attributed to the increase in the pinning force, so that the screening current density becomes subcritical. The last statement is corroborated by direct measurements.     

Wave-trapped particle interaction in a weak transverse magnetic field

Damping of an electrostatic plasma wave loaded with a small density bunches of trapped electrons and propagating across a weak magnetic field is studied. To describe the time evolution of the wave, simple algebraic equations are derived under some restrictions on the parameters of the physical system. It is shown that the nonlinear frequency shift of the wave due to the presence of the trapped particles plays an important role and must be taken into account in the self-consistent treatment of the wave–particle interaction.     

Magnetotransport in a semconductor superlattice with transverse magnetic field

Magnetotransport in a semiconductor superlattice (SL) under transverse magnetic field has been investigated. It is shown that in weak magnetic and electric fields there is negative magnetoresistivity along the SL layers and positive magnetoresistivity along the SL axis. The Hall resistivity is much less than the usual semiconductor value. With an increase of electric field, there appears a negative differential conductivity (NDC) along the SL layers, and the Hall voltage depends nonlinearly on current density. In higher electric field, destroying the miniband structure, the magnetoresistivity along the SL axis is negative. The magnetoresistivity along the SL axis in strong magnetic field is positive for any current density. The Hall resistivity in strong magnetic (electric) field equals the classical value.     

Thermo-emf of InSb in a transverse quantizing magnetic field

We have measured the thermo-emf of n-type indium antimonide in a transverse quantizing magnetic field. The results are explained using a theory that includes splitting of the Landau levels.Physics Institute of the Dagestanskii Center, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 26–29, March, 1993.     

Quasi-one-dimensional anisotropic Heisenberg model in a transverse magnetic field

The phase diagram of weakly coupled XXZ chains in a transverse magnetic field is studied using the mean-field approximation for the interchain coupling and known exact results for an effective one-dimensional model. The results are applied to the quasi-one-dimensional antiferromagnet Cs₂CoCl₄, and the value of interchain interaction in this compound is estimated.     

The quantum compass chain in a transverse magnetic field

We study the magnetic behaviors of a spin-1/2 quantum compass chain (QCC) in a transverse magnetic field, by means of the analytical spinless fermion approach and numerical Lanczos method. In the absence of the magnetic field, the phase diagram is divided into four gapped regions. To determine what happens by applying a transverse magnetic field, using the spinless fermion approach, critical fields are obtained as a function of exchanges. Our analytical results show, the field-induced effects depend on in which one of the four regions the system is. In two regions of the phase diagram, the Ising-type phase transition happens in a finite field. In another region, we have identified two quantum phase transitions (QPT)s in the ground state magnetic phase diagram. These quantum phase transitions belong to the universality class of the commensurate-incommensurate phase transition. We also present a detailed numerical analysis of the low energy spectrum and the ground state magnetic phase diagram. In particular, we show that the intermediate state (h _c1 < h < h _c2) is gapful, describing the spin-flop phase.     

Dynamical susceptibility of the ising model in a transverse magnetic field

An approximate expression is obtained for the dynamical susceptibility, χ_zz(q, ω), of the spin one half, simple cubic Ising model in a transverse magnetic field, which is appropriate to the disordered state (〈S_z〉 = 0). The susceptibility along the direction of the field is shown to contain a thermal part with a relative weight proportional to the difference between the isothermal and adiabatic susceptibilities and a width determined by the thermal diffusion constant.     

Intensive ion beams in the transverse magnetic field of anelectromagnetic separator

Based on state-of-the-art knowledge, the processes of the formation of intense ion beams in the transverse magnetic field of a commercial electromagnetic separator are analyzed. It is shown that, given the conditions of closed electron drift, the potentials will surely equalize along the fast ion trajectories all the way through the beam length; hence, no improvement in dynamic decompensation is caused by the low-frequency noise of the source. It is established that increasing the full beam current forces the maximum amplitude of the current density oscillations out to the beam periphery crosswise. For the first time, it is shown that suppressing noise oscillations in the arc discharge of an ion source for the formation of a highly stable ion beam with a minimum inner potential drop is possible. At low pressures, with collective interaction out of play, the drop is determined by Coulomb's collisions between the beam particles and compensating electrons. The analysis of collective phenomena likely to occur in the ion-beam plasma of a separator gives evidence of an experimental space potential buildup with increasing residual gas pressure in the calutron, leading to a high-frequency ion-electron beam instability. It is pointed out that this instability combined with an additional decompensation results in a noticeable broadening of the beam energy spectrum, which in turn makes for a lower quality of separation     

MHD shear flows with non-constant transverse magnetic field

Viscous conducting flows parallel to a fixed plate are studied. In contrast with the Hartmann setting, the problem is not linearized near a fixed transverse magnetic field, although the field tends to be transversal far from the wall. While general solutions may be formally obtained for all cases, their behavior is far more clear when the magnetic Prandtl number equals one. We consider two different instances: a fixed magnetic field at the wall, or an insulating sheet. The evolution of the flow and the magnetic field both near the plate and far from it are detailed, analyzing the possibility of reverse flow and instability of the solutions.     

Focusing of electrons by a transverse magnetic field

The foundations of the focusing of electrons by a transverse magnetic field proposed by V.S. Tsoi in 1974 have been reviewed. The kinetics of electrons in condensed media and interactions of conduction electrons with interfaces has been studied by means of the focusing of electrons. Various applications of the focusing of charge carriers in low-dimensional, including two-dimensional, electron systems have been demonstrated.     

Investigation of magneto-optical effect in transverse magnetic field in He

The non-linear Voigt effect has been studied in He discharge under resonance laser interaction with the He transition. The range of non-linear signal existence was determined. The contribution of the lower and upper states to the overall signal was analyzed. The cross-section for depolarizing collisions with ground state He atoms was estimated for the 3³ D _2,3 He state. Received: 16 June 1998 / Received in final form: 14 December 1998     

Exciton polaritons in quantum wells in a transverse magnetic field

Physics of the Solid State - This paper reports on a study of the exciton polariton region in reflection spectra of wide CdTe/CdZnTe quantum wells (with well width exceeding by far the exciton Bohr...     

Superconducting plate in a transverse magnetic field: New state

A model is proposed for describing Cooper pairs near the transition (in temperature and magnetic field) point when their spacing is larger than their size. The essence of the model is as follows: the Ginzburg-Landau functional is written in operator form in terms of field operators of the Bose type so that the average value of the density operator gives the concentration of Cooper pairs, and the same Ginzburg-Landau expression is obtained for the Bose condensate. The model is applied to a superconducting plate with a thickness smaller than the size of a pair in a transverse magnetic field near its upper critical value H _c2. A new state is discovered that is energetically more advantageous in a certain interval in the vicinity of the transition point as compared to the Abrikosov vortex state. The wavefunction of the system in this state is of the type of the Laughlin function used in the fractional quantum Hall effect (naturally, as applied to Cooper pairs as Bose particles in our case) and corresponds to a homogeneous incompressible fluid. The energy of this state is proportional to the first power of quantity (1 ? H/H _c2) in contrast to the energy of the vortex state containing the square of this quantity. The interval of the existence of the new state is the larger, the dirtier the sample.