Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userInvestigation of stimulated dynamics in strongly anisotropic high-temperature superconductors system Bi-Pb-Sr-Ca-Cu-O
310
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
It is used the mechanical method of Abrikosov vortex stimulated dynamics investigation in superconductors. With its help it was studied relaxation phenomena in vortex matter of high-temperature superconductors. It established that pulsed magnetic fields change the course of relaxation processes taking place in vortex matter. The study of the influence of magnetic pulses differing by their durations and amplitudes on vortex system of strongly anisotropic high-temperature superconductors system Bi1.7Pb0.3Sr2Ca2Cu3O10-d showed the presence of threshold phenomena. The small duration pulses do not change the course of relaxation processes taking place in vortex matter. When the duration of pulses exceeds some critical value (threshold), then their influence change the course of relaxation process which is revealed by stepwise change of relaxing mechanical moment.. These investigation showed that the time for formatting of Abrikosov vortex lattice in Bi1.7Pb0.3Sr2Ca2Cu3O10-d is of the order of 150 us which on the order of value exceeds the time necessary for formation of a single vortex observed in isotropic high-temperature superconductor HoBa2Cu3O7-d and on two orders exceeds the creation time of a single vortex observed in classical type II superconductors.
rate research
Read More
The work is related with the finding out of magnetic phases in strongly anisotropic high-temperature superconductor Bi1,7Pb0,3Sr2Ca2Cu3O10-d in the temperature region where the superconductor is in the normal state. It was studied the temperature dependence of the paramagnetic probe EPR line width. In the normal state at T>Tc near 175 K it was revealed a pick in the temperature dependence of line width. In this region it was observed the time increase of the line width with the characteristic time ~ 17 min. This shows the possibility of magnetic phase formation in this material.
Using the high-sensitive mechanical method of measuring the dissipation processes in superconductors, the 3D-2D phase transition in magnetic field was investigated in the vortex lattice of strongly anisotropic high-temperature superconductors of Bi(2223) system. It was shown that with the increase of external magnetic field the dissipation connected with a motion of vortexes relative to the crystal lattice of a sample, first increases, reaching the maximum and then with a further increase of the magnetic field sharply reduces as a result of pinning enhancement in connection with the transition of three-dimensional vortex system in quasi-two-dimensional pancake one.
A simple mechanical method for the investigation of Abrikosov vortex lattice stimulated dynamics in superconductors has been used. By this method we studied the action of pulsed magnetic fields on the vortex lattice and established the resulting change of the course of relaxation processes in the vortex matter in high-temperature superconductors. This method can be used for investigation of phase transitions in vortex matter both high-temperature and exotic superconductors.
We report an ARPES investigation of the circular dichroism in the first Brillouin zone (BZ) of under- and overdoped Pb-Bi2212 samples. We show that the dichroism has opposite signs for bonding and antibonding components of the bilayer-split CuO-band and is antisymmetric with respect to reflections in both mirror planes parallel to the c-axis. Using this property of the energy and momentum intensity distributions we prove the existence of the bilayer splitting in the normal state of the underdoped compound and compare its value with the splitting in overdoped sample. In agreement with previous studies the magnitude of the interlayer coupling does not depend significantly on doping. We also discuss possible origins of the observed dichroism.
We examine the redistribution of the in-plane optical spectral weight in the normal and superconducting state in tri-layer bbb (Bi2223) near optimal doping ($T_c$ = 110 K) on a single crystal via infrared reflectivity and spectroscopic ellipsometry. We report the temperature dependence of the low-frequency integrated spectral weight $W(Omega_c)$ for different values of the cutoff energy $Omega_c$. Two different model-independent analyses consistently show that for $Omega_c$ = 1 eV, which is below the charge transfer gap, $W(Omega_c)$ increases below $T_c$, implying the lowering of the kinetic energy of the holes. This is opposite to the BCS scenario, but it follows the same trend observed in the bi-layer compound bb (Bi2212). The size of this effect is larger in Bi2223 than in Bi2212, approximately scaling with the critical temperature. In the normal state, the temperature dependence of $W(Omega_c)$ is close to $T^2$ up to 300 K.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
