Abrikosov fluxoid pinning in Al-13.5 at % Ag alloy by magnetic and torque measurements

Abstract

The pinning force in a supersaturated solid solution orAl-13.5 at % Ag with defect structures of various types (Guinier-Preston zones, y'-and y-phase lamellae) formed by isothermal aging treatment has been investigated. To determine the fluxoid pinning force, both mechanical and magnetic techniques were used. At the same time transmission electron microscopy and optical microscopy observations were carried out. An increase of the pinning force with the decay of the alloy was observed.

Investigation of stimulated dynamics in strongly anisotropic high-temperature superconductors system Bi–Pb–Sr–Ca–Cu–O

“…In the first (initial) region, the sample does not respond to the increase in ω ω = one could find similarly to [24,25] the expression for the total braking torque τ [19]. If in this region the torsion head is stopped, then at the expense of relaxation processes connected with the presence of viscous forces acting on vortex filaments, the sample will continue the rotation in the same direction (with decreasing velocity) until it reaches a certain equilibrium position, depending on the value.…”

“…This method is a development of currentless mechanical method of pinning investigations [17,18] and is based on pinning forces countermoments measurements and viscous friction, acting on a axially symmetrical superconducting sample in an outer (transverse) magnetic field. Countermoments of pinning forces and of viscous friction, acting on a superconductive sample from quantized vortex lines side (Abrikosov vortices) are defined the way as it was described in work [19,20]. The sensitivity of the method accordingly work [21] In experiments it was used both single and continuous pulsed with repetition frequency ν from 2.5 s -1 to 500s -1 .…”

“…The principal set-up of experiment is shown in fig.1 [19,20]. In experiments it is measured the rotation angle To avoid effects, connected with the frozen magnetic fluxes, the lower part of the cryostat with the sample was put into a special cylindrical Permalloy screen, reducing the Earth magnetic field by the factor of 1200.…”

Investigation of relaxation phenomena in high-temperature superconductors HoBa2Cu3O7−δ at the action of pulsed magnetic fields

“…This method is a development of a currentless mechanical method of pinning investigations [20,21] and is based on pinning forces countermoments measure- ments and viscous friction, acting on an axially symmetrical superconducting sample in an outer (transverse) magnetic field. Countermoments of pinning forces and of viscous friction, acting on a superconductive sample from quantized vortex lines side (Abrikosov vortices) are defined in the way as it was described in work [22,23]. The sensitivity of the method accordingly works [24], is equivalent to 10 −8 V cm −1 in the method of V −A characteristics.…”

Investigation of stimulated dynamics of vortex matter in high-temperature superconductors

“…The mechanical method of investigation of the stimulated dynamics of the Abrikosov vortex lattice, proposed by us, is the development of a currentless mechanical method of the investigation of pinning [21,22] based on the measurement of the mechanical moment acting on the 2 superconducting sample with axial symmetry, which is located in an external (transverse) magnetic field. Countermoments of pinning forces and of viscous friction, acting on the sample from the side of quantized vortex lines (Abrikosov vortices) were determined as in [23,24]. The isotropic ceramic HoBa 2 Cu 3 O 7-δ sample was prepared by the standard solid state reaction.…”