arXiv subjects

A. Yu. Zyuzin

Publications and source records attributed to A. Yu. Zyuzin.

25 records · Page 2Linked to original sources

arXiv2007

Effect of electron interactions on the conductivity and exchange coupling energy of disordered metallic magnetic multilayer

We consider the effect of electron-electron interactions on the current-in-plane (CIP) conductivity and exchange coupling energy of a disordered metallic magnetic multilayer. We analyze its dependence on the value of ferromagnetic splitting of conducting electrons and ferromagnetic layers relative magnetizations orientation. We show that contribution to the CIP conductivity and exchange coupling energy as a periodic function of the angle of magnetizations relative orientation experience $ 2π\to π$ transition depending on the characteristic energies: ferromagnetic splitting of the conducting electrons and the Thouless energy of paramagnetic layer.

cond-mat.mes-hall↗

arXiv2007

Resistivity effects in surface superconductivity of thin films in strong magnetic fields

Phase slips creation in the thin film in perpendicular magnetic filed with edge superconductivity is studied. These centers are due to thermal activation of the order parameter below superconducting temperature transition leading to the suppression of the superconductivity. The corresponding resistance is calculated. The Alsamazov- Larkin correction to the conductivity above the critical magnetic field destroying the surface superconductivity is studied. Such structures could be applied as a new system for the study of the phase slip phenomenon in one- dimensional superconducting wires.

cond-mat.supr-con↗

arXiv2004

Anomalous magnetotransport in (Y$_{1-x}$Gd$_{x}$)Co$_{2}$ alloys: interplay of disorder and itinerant metamagnetism

New mechanism of magnetoresistivity in itinerant metamagnets with a structural disorder is introduced basing on analysis of experimental results on magnetoresistivity, susceptibility, and magnetization of structurally disordered alloys (Y$_{1-x}$Gd$_{x}$)Co$_{2}$. In this series, YCo$_{2}$ is an enhanced Pauli paramagnet, whereas GdCo$_{2}$ is a ferrimagnet (T$_{\rm c}$=400 K) with Gd sublattice coupled antiferromagnetically to the itinerant Co-3d electrons. The alloys are paramagnetic for $x < 0.12$. Large positive magnetoresistivity has been observed in the alloys with magnetic ground state at temperatures T$<$T$_{\rm c}$. We show that this unusual feature is linked to a combination of structural disorder and metamagnetic instability of itinerant Co-3d electrons. This new mechanism of the magnetoresistivity is common for a broad class of materials featuring a static magnetic disorder and itinerant metamagnetism.

cond-mat.str-el↗

arXiv2002

Mesoscopic effects in superconductor-ferromagnet-superconductor junctions

We show that at zero temperature the supercurrent through the superconductor - ferromagnetic metal - superconductor junctions does not decay exponentially with the thickness $L$ of the junction. At large $L$ it has a random sample-specific sign which can change with a change in temperature. In the case of mesoscopic junctions the phase of the order parameter in the ground state is a random sample-specific quantity. In the case of junctions of large area the ground state phase difference is $\pm π/2$.

cond-mat.supr-con↗

arXiv1998

Correlations in Transmission of Light through a Disordered Amplifying Medium

The angular and frequency correlation functions of the transmission coefficient for light propagation through a strongly scattering amplifying medium are considered. It is found that just as in the case of an elastic scattering medium the correlation function consists of three terms. However, the structure of the terms is rather different. Angular correlation has a power-law decay and exhibits oscillations. There is no "memory effect" as in the case of an elastic medium. Interaction between diffusion modes is strongly enhanced near the lasing threshold. Frequency correlation scale decreases close to the lasing threshold. We also consider time correlations of the transmission in the case of nonstationary inhomogeneities. We find short- and long-range time correlations. The scale of the short-range correlation decreases, while the long-range correlation scale becomes infinite near the threshold.

cond-mat.mes-hall↗

arXiv1997

Is the magnetic field necessary for the Aharonov-Bohm effect in mesoscopics?

A new class of topological mesoscopic phenomena in absence of external magnetic field (meso-nucleo-spinics)is predicted, which is based on combined action of the nonequilibrium nuclear spin population and charge carriers spin-orbit interaction . As an example, we show that Aharonov-Bohm like oscillations of the persistent current in GaAs/AlGaAs based mesoscopic rings may exist, in the absence of the external magnetic field, provided that a topologically nontrivial strongly nonequilibrium nuclear spin population is created. This phenomenon is due to the breaking, via the spin-orbit coupling, of the clock wise - anti clock wise symmetry of the charge carriers momentum, which results in the oscillatory in time persistent current.

cond-mat.mes-hall↗

arXiv1996

Orbital Magnetism of 2D Chaotic Lattices

We study the orbital magnetism of 2D lattices with chaotic motion of electrons withing a primitive cell. Using the temperature diagrammatic technique we evaluate the averaged value and rms fluctuation of magnetic response in the diffusive regime withing the model of non-interacting electrons. The fluctuations of magnetic susceptibility turn out to be large and at low temperature can be of the order of $χ_{L} (k_{F}l)^{3/2}$, where $k_{F}$ is the Fermi wavevector, $l$ is the mean free path, and $χ_{L}$ is the Landau susceptibility. In the certain region of magnetic fields the paramagnetic contribution to the averaged response is field independent and larger than the absolute value of Landau response.

cond-mat↗