Vortex Pinning in Microindented Yba2Cu3O7-x Single Crystals

Published

August 1, 2000

Author(s)

Marina Turchinskaya, Douglas T. Smith, Alexander L. Roytburd, Debra L. Kaiser

Abstract

A high resolution magneto-optical technique with a magnetic indicator film was used to study the effect of a regular array of micrometer-sized mechanical indentations on magnetization dynamics at the surface of a twinned single crystal of Yba₂Cu₃O_{7-δ as a function of applied magnetic field, H}da^ (O to 68 mT) at temperatures in the range of 10-70 K. Direct visualization of the magnetic flux interaction with the individual indentations was observed for the first time. During magnetization at low H_a up to 15 mT at 60 K, the first row of indentations provides resistance to the flux front. In the indented area, flux is preferably pinned at the indentation sites. With increasing H_a, the vortex density at the indentations approaches the magnetic flux density in the surrounding material. During demagnetization down to H_a = 0mT, the outgoing flux is trapped by the indentations in areas where the density of the trapped flux is small; flux is also trapped along the (110) twin boundaries behind the indentations. For H_a = 0 to 10 mT, the average value of the magnetic induction gradient in the vicinity of an indentation is {approximately equal to} 0.4 mT/ m at 20-60 K. The average induction gradient and, thus, the critical current density in the indented material is estimated to be 1.5-2 times greater than in the unindented material at temperatures from 10 to 70 K and H_a from 18 to 68 mT.

Citation

Journal of Applied Physics

Volume

88

Issue

No. 3

Pub Type

Journals

Keywords

artificial defects, flux pinning, HTSC, magneto-optical imaging, twin boundaries

Citation

Turchinskaya, M. , Smith, D. , Roytburd, A. and Kaiser, D. (2000), Vortex Pinning in Microindented Yba₂Cu₃O_7-x Single Crystals, Journal of Applied Physics (Accessed April 20, 2024)