Magnetic polarons in Y-Ba-Cu-O chains

Mossbauer spectroscopy is used to study electron self-localization in the superconducting cuprate paramagnetic compound Y-Ba-Cu-O. It is shown that the electrons in chains with self-localization form a phase with local magnetic ordering and relaxation time greater than 10(-7) s. Analysis of the magnitude of the accompanying charge redistribution suggests that when an electron undergoes self-localization a pair of exchange-coupled electrons localized predominantly on the oxygen is formed. Such a quasiparticle, consisting of a pair of antiferromagnetically oriented atomic moments and a pair of self-localized electrons, possesses integral spin and can form a Bose condensate. (C) 2002 American Institute of Physics.