ESR-SPECTRA AND LOW-FIELD MICROWAVE-ABSORPTION IN BISMUTH AND THALLIUM BASED CUPRATE SUPERCONDUCTORS
Journal
Japanese Journal of Applied Physics Part 2-Letters
Journal Volume
29
Journal Issue
2
Pages
L258-L261
Date Issued
1990
Author(s)
Abstract
Electron Spin Resonance and low-field microwave absorption are reported for a range of Bi- and Tl-based superconductors in the Bi-Ca-Sr-Cu-O, Bi(Pb)-Ca-Sr-Cu-O and Tl-Ca-Ba-Cu-O series together with the new monophasic series (Tl 0.5 Pb 0.5 )(Ca 0.8 A 0.2 )Sr 2 Cu 2 O y (A=Y or Er) superconductors. In contrast to two recent reports of ESR in the Tl-Ca-Ba-Cu-O and Bi(Pb)-Ca-Sr-Cu-O systems, we find: (i) no evidence of any “intrinsic” Cu 2+ ESR signals close to the free spin region, and (ii) no evidence of a (low-field) microwave absorption at temperatures above T c . The question of ESR silence in these oxide superconductors and related phases is discussed.
Type
journal article