Antiferromagnetism in hydrated 123 compounds
Dooglav A.V., Egorov A.V., Mukhamedshin I.R., Savinkov A.V., Alloul H., Bobroff J., MacFarlane W.A., Mendels P., Collin G., Blanchard N., Picard P.G.
PACS: 74.25.Nf, 74.72.Bk, 75.50.Ee
Copper nuclear quadrupole resonance and zero field nuclear magnetic resonance studies of õ÷ÁÇóÉÚï×.Â show that a magnetic phase appears in underdoped 123 superconductors treated in ambient wet air. The studies give convincing evidence that the "empty" óÉ ï chains play the role of easy water insertion channels. The reaction occurs first in ordered regions of the crystallites. The final product of the reaction is a non-superconducting antiferromagnetic compound characterized by at least two types of magnetically ordered copper ions with ZFNMR spectra respectively in the frequency ranges of 46-96 and 96-135 MHz respectively. Even for powder samples fixed in an epoxy resin, the reaction is found to occur partly after a few years.