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EPR Measurements on the Cu 2+ Ion in the High‐ T c Superconductors MBa 2 Cu 3 O 7 – δ
Author(s) -
Guskos N.,
Londos C. A.,
Trikalinos Ch.,
Paraskevas S. M.,
Koufoudakis A.,
Mitros C.,
GamariSeale H.,
Niarchos D.
Publication year - 1991
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221650121
Subject(s) - electron paramagnetic resonance , superconductivity , orthorhombic crystal system , ion , lanthanide , crystallite , materials science , crystallography , atmospheric temperature range , condensed matter physics , chemistry , crystal structure , nuclear magnetic resonance , physics , organic chemistry , meteorology
EPR studies are carried out on the polycrystalline high‐ T c superconductors MBa 2 Cu 3 O 7 – δ (M = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Tm, Yb and Lu). The onset of the superconducting transition is found to occur in the temperature range of 90 to 95 K (except for LaBa 2 Cu 3 O 7 – δ where T c = 50 K and PrBa 2 Cu 3 O 7 – δ which is not superconducting for temperatures above 4.2 K). In all of these compounds an EPR spectrum of Cu 2+ ions in the orthorhombic local symmetry, is observed. The signal intensities are found to depend strongly on the particular rare‐earth ions of the lanthanide series which are substitutionally introduced into the host lattice of YBa 2 Cu 3 O 7 – δ at Y‐ions site. “Skin effect” is suggested to be the main cause of the observed changes in the intensity of EPR signals.