Lambert formula - Bouguer absorption law?

It is shown that the fundamental Bouguer law, which links the fraction of absorbed light to the intensity of the incident light for a constant thickness of absorbing layer, was discovered experimentally and that the Lambert law is in no way related to it. The Lambert formula can be used only to estimate the attenuation (transmission) of light in a homogeneous medium containing scattering heterogeneous particles and with no jumps of the refractive index. The fraction of light absorbed in a layer is shown to depend on the thickness of that layer. © 1998 Plenum Publishing Corporation

Critical temperature of superconductor/ferromagnet bilayers

Superconductor/ferromagnet bilayers are known to exhibit nontrivial dependence of the critical temperature T_c on the thickness d_f of the ferromagnetic layer. We develop a general method for investigation of T_c as a function of the bilayer's parameters. It is shown that interference of quasiparticles makes T_c(d_f) a nonmonotonic function. The results are in good agreement with experiment. Our method also applies to multilayered structures.Comment: 4 pages, 2 EPS figures; the style file jetpl.cls is included. Version 2: typos correcte

Evidence for two-dimensional nucleation of superconductivity in MgB2_{2}

According to the crystal structure of MgB$_{2}$ and band structure calculations quasi-two-dimensional (2D) boron planes are responsible for the superconductivity. We report on critical fields and resistance measurements of 30 nm thick MgB$_{2}$ films grown on MgO single crystalline substrate. A linear temperature dependence of the parallel and perpendicular upper critical fields indicate a 3D-like penetration of magnetic field into the sample. Resistivity measurements, in contrast, yield a temperature dependence of fluctuation conductivity above T$_{c}$ which agrees with the Aslamazov-Larkin theory of fluctuations in 2D superconductors. We consider this finding as an experimental evidence of two-dimensional nucleation of superconductivity in MgB$_{2}$.Comment: 5 RevTex pages, 3 PostScript Figures ZIPed in archive Sidoren.zip. Submitted to EuroPhys. Lett. December 3, 200

Ballistic magnetoresistance in nickel single-atom conductors

Large ballistic magnetoresistance (BMR) has been measured in Ni single-atom conductors electrodeposited between microfabricated thin films. These measurements irrefutably eliminate any magnetostriction related artifacts in the BMR effect.Comment: 12 pages, 3 Figure

Magnetic and superconducting heterostructures in spintronics

This paper is a brief review of investigations, which were carried out during last years by team of magnetic nanostructures and spintronics laboratory, and is dedicated to the 80th anniversary of our Teacher - professor B.I. Kochelaev. © Kazan Federal University (KFU)

Magnon bottleneck emergence in La2-xSrxCuO4+δ and its use in studies of the dynamics of CuO2 planes

An improved model of the magnon bottleneck is used to show the possibility of measuring the relaxation rate to a homogeneous magnetization lattice of copper-oxygen planes in copper oxide. The agreement between EPR measurements of the spin dynamical characteristics in CuO2 planes and data obtained by NMR spectroscopy is proven to be adequate. © 1996 American Institute of Physics

Experimental and theoretical analysis of the upper critical field in FSF trilayers

The upper critical magnetic field H_{c2} in thin-film FSF trilayer spin-valve cores is studied experimentally and theoretically in geometries perpendicular and parallel to the heterostructure surface. The series of samples with variable thicknesses of the bottom and of the top Cu_{41}Ni_{59} F-layers are prepared in a single run, utilizing a wedge deposition technique. The critical field H_{c2} is measured in the temperature range $0.4-8$ K and for magnetic fields up to 9 Tesla. A transition from oscillatory to reentrant behavior of the superconducting transition temperature versus F-layers thickness, induced by an external magnetic field, has been observed for the first time. In order to properly interpret the experimental data, we develop a quasiclassical theory, enabling one to evaluate the temperature dependence of the critical field and the superconducting transition temperature for an arbitrary set of the system parameters. A fairly good agreement between our experimental data and theoretical predictions is demonstrated for all samples, using a single set of fit parameters. This confirms adequacy of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) physics in determining the unusual superconducting properties of the studied Cu_{41}Ni_{59}/Nb/Cu_{41}Ni_{59} spin-valve core trilayers.Comment: 16 pages, 7 figures; published versio

Memory Effect and Triplet Pairing Generation in the Superconducting Exchange Biased Co/CoOx/Cu41Ni59/Nb/Cu41Ni59 Layered Heterostructure

We fabricated a nanolayered hybrid superconductor-ferromagnet spin-valve structure, the resistive state of which depends on the preceding magnetic field polarity. The effect is based on a strong exchange bias (about -2 kOe) on a diluted ferromagnetic copper-nickel alloy and generation of a long range odd in frequency triplet pairing component. The difference of high and low resistance states at zero magnetic field is 90% of the normal state resistance for a transport current of 250 {\mu}A and still around 42% for 10 {\mu}A. Both logic states of the structure do not require biasing fields or currents in the idle mode.Comment: 9 pages, 4 figures, Accepted to Applied Physics Letter