Related papers: Microwave Response of Ceramic MgB2 Samples
The two-gap structure in the superconducting state of MgB_2 gives rise to unusual thermodynamic properties which depart markedly from the isotropic single-band BCS model, both in their temperature- and field dependence. We report and…
Studies on the new MgB2 superconductor, with a critical temperature Tc ~ 39 K, have evidenced its potential for applications although intense magnetic relaxation effects limit the critical current density, Jc, at high magnetic fields. This…
We report on the temperature dependence of microwave-induced resistance oscillations in high-mobility two-dimensional electron systems. We find that the oscillation amplitude decays exponentially with increasing temperature, as…
The microwave response of high quality niobium films in a perpendicular static magnetic field has been investigated. The complex frequency shift was measured up to the upper critical fields. The data have been analyzed by the effective…
We report on the magnetic-field-induced variations of the microwave surface resistance, R_s, in a polycrystalline MgB_2 sample, at different values of temperature. We have detected a magnetic hysteresis in R_s, which exhibits an unexpected…
We consider the far-infrared and the microwave conductivities of a two-band superconductor with non-magnetic impurities. The strong coupling expressions for the frequency and temperature dependent conductivity of a two-band superconductor…
The resistivity and magnetoresistance in the normal state for bulk and thin-film MgB2 with different nominal compositions have been studied systematically. These samples show different temperature dependences of normal state resistivity and…
We have studied an anomalous microwave (mw) response of superconducting YBa_{2}Cu_{3}O_{7-delta} (YBCO) microstrip resonators in the presence of a weak dc magnetic field, H_{dc}. The surface resistance (R_{s}) and reactance (X_{s}) show a…
The response of two-dimensional electron gas to temperature gradient in perpendicular magnetic field under steady-state microwave irradiation is studied theoretically. The electric currents induced by temperature gradient and the…
Abstract We study the temperature dependence of the absorption of microwaves by random-anisotropy magnets. It is governed by strong metastability due to the broad distribution of energy barriers separating different spin configurations. At…
We report measurements of the microwave surface impedance of the borocarbide family of superconductors LnNi2B2C (Ln=Y, Er, Tm, Ho). The experiments enable direct measurements of the superfluid density, and are particularly sensitive to the…
The temperature dependence of the microwave surface impedance and conductivity are used to study the pairing symmetry and properties of cuprate superconductors. However, the superconducting properties can be hidden by the effects of…
The nonlinear surface resistance Rs of the YBa2Cu3O7-x superconducting thin films on the MgO substrates was researched in the Hakki-Coleman dielectric resonator at the microwave signal powers from -18 dBm to +30 dBm at the ultra high…
We report experimental results of the field-induced variations of the microwave surface resistance in samples of MgB2, produced by different methods. By sweeping the DC magnetic field at increasing and decreasing values, we have detected a…
We calculate the intrinsic nonlinear microwave response of the two gap superconductor MgB2 in the clean and dirty limits. Due to the small value of the pi band gap, the nonlinear response at low temperatures is larger than for a single gap…
The angular and temperature dependence of the upper critical field Hc2 in MgB2 was determined from torque magnetometry measurements on single crystals. The Hc2 anisotropy gamma_H was found to decrease with increasing temperature, in…
Upper critical fields of four MgB2 thin films were measured up to 28 Tesla at Grenoble High Magnetic Field Laboratory. The films were grown by Pulsed Laser Deposition and showed critical temperatures ranging between 29.5 and 38.8 K and…
The microscopic superconductivity theory in MgB2 systems in the magnetic fields directed parallel and perpendicular to the plane (ab) is built. The two energy bands of different dimensions overlapping on the Fermi surface (two-dimensional…
We have measured the normal state temperature dependence of the Hall effect and magnetoresistance in epitaxial MgB2 thin films with variable disorders characterized by the residual resistance ratio RRR ranging from 4.0 to 33.3. A strong…
To study the influence of microwave irradiation on two-dimensional electrons, we apply a method based on capacitance measurements in GaAs quantum well samples where the gate covers a central part of the layer. We find that the capacitance…