DENSITY-OF-STATES AND MAGNETIC CORRELATIONS IN THE LA2-XSRXCUO4 SYSTEM STUDIED BY EPR OF FE SPIN PROBES

Citation
Ad. Shengelaya et al., DENSITY-OF-STATES AND MAGNETIC CORRELATIONS IN THE LA2-XSRXCUO4 SYSTEM STUDIED BY EPR OF FE SPIN PROBES, Physica. C, Superconductivity, 233(1-2), 1994, pp. 124-130
Citations number
24
Categorie Soggetti
Physics, Applied
ISSN journal
09214534
Volume
233
Issue
1-2
Year of publication
1994
Pages
124 - 130
Database
ISI
SICI code
0921-4534(1994)233:1-2<124:DAMCIT>2.0.ZU;2-2
Abstract
EPR of Fe3+ ions doped to La2-xSrxCuO4 samples with various Sr content (x=0-0.25) has been carried out. In the high-temperature region the E PR linewidth was determined by the Korringa relaxation. By extracting the Korringa contribution, we were able to evaluate a dependence of th e density of states N-F on X. It has been found that N-F continuously grows with Sr doping from under- to overdoped regimes. The obtained N- F(x) dependence indicates that the insulator-metal transition near x=0 .06 is driven by hole delocalization. In the low-temperature region th e relaxation rate was determined by spin-spin relaxation. The low-temp erature upturn observed for the temperature dependence of the EPR line width can be understood by a slowing down of spin fluctuations due to spin freezing and/or carrier localization. We suggest that carrier loc alization enhancement plays an important role in the occurrence of the well known anomaly of T-c near x = 0.125 (so-called 1/8 problem).