: A candidate system for purely oxygen antiferromagnet?
Moscow State University - 119899, Moscow, Russia
2 Ural State University - 620083, Ekaterinburg, Russia
3 Max Planck Institut für Chemische Physik Fester Stoffe D-01187, Dresden, Germany
4 Leibniz Institut für Festkörper- und Werkstofforschung Dresden D-01171, Dresden, Germany
5 TU-Clausthal, Institut für Mineralogie und Mineralische Rohstoffe D-38678, Clausthal-Zellerfeld, Germany
Accepted: 18 May 2003
Nuclear quadrupole resonance (-NQR) measurements in have revealed an unexpected puzzling picture evidencing the absence of a noticeable local hyperfine magnetic field on nuclei in the antiferromagnetically ordered state below , and considerable charge redistribution as compared with the counterpart system. Unconventional “nonmagnetic” behavior of copper ions in points to a possibly nonmagnetic copper valent state with antiferromagnetically ordered oxygen surroundings. It means that the hole in the cell should be localized at oxygen, rather than at copper sites. We suggest a qualitative physical reasoning for the “sp hybridization induced oxygen hole stabilization effect” which is believed to be more pronounced in as compared with .
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 71.28.+d – Narrow-band systems; intermediate-valence solids / 76.60.-k – Nuclear magnetic resonance and relaxation
© EDP Sciences, 2003