Peculiar charge localization and cluster-spin-glass-like behaviour in underdoped
Superconductivity Research Laboratory, ISTEC
1-10-13 Shinonome, Koto-ku, Tokyo 135-0062, Japan
Corresponding author: firstname.lastname@example.org
Accepted: 16 July 2001
We report on the out-of- and in-plane resistivity results in underdoped superconducting (SC) crystals that show a pronounced upturn in resistivity followed by a SC or metallic state at low temperature for . The resistivity and the magnetization exhibit an unusual upturn and irreversibility, respectively, at the same temperature, suggesting a peculiar charge localization and a cluster-spin-glass-like behaviour, probably due to magnetic ordering with low-energy magnetic fluctuations. The thermomagnetic and magnetic hysteresis, and relaxation indicate the presence of an actual frozen cluster-spin-glass-like state at low temperature, where spin fluctuations slow down significantly. Our results indicate that the metal-insulator-like upturn in resistivity and thermomagnetic history effects have a common origin.
PACS: 74.25.-q – Superconductivity: General properties; correlations between physical properties in normal and superconducting states / 74.25.Fy – Transport properties (electric and thermal conductivity, thermoelectric effects, etc) / 74.25.Ha – Magnetic properties
© EDP Sciences, 2001