Nuclear magnetic resonace sNMRd, EPR and magnetization measurements in NaxCoO2 for 0.65<x<0.75 are presented. While the EPR signal arises from Co4+ magnetic moments ordering at Tc.26 K, 59Co NMR signal originates from cobalt nuclei in metallic regions with no long range magnetic order and characterized by a generalized susceptibility typical of strongly correlated metallic systems. This phase separation in metallic and magnetic insulating regions is argued to occur below T*(x) (220–270 K). Above T* an anomalous decrease in the intensity of the EPR signal is observed and associated with the delocalization of the electrons which for T<T* were localized on Co4+ dz2 orbitals. It is pointed out that the in-plane antiferromagnetic coupling J <<T* cannot be the driving force for the phase separation.
Mesoscopic phase separation in NaxCoO2 (0.65
CARRETTA, PIETRO;MARIANI, MANUEL;MOZZATI, MARIA CRISTINA;
2004-01-01
Abstract
Nuclear magnetic resonace sNMRd, EPR and magnetization measurements in NaxCoO2 for 0.65
CARRETTA, PIETRO;MARIANI, MANUEL;MOZZATI, MARIA CRISTINA;
2004-01-01
Abstract
Nuclear magnetic resonace sNMRd, EPR and magnetization measurements in NaxCoO2 for 0.65I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
