Large distinctions between underdoped and overdoped La 2−xSr xCuO 4 single crystals as observed from magnetic and transport measurement: A possible evidence for macroscopic phase separation in overdoped high temperature superconductors

Abstract

Magnetic and DC transport properties have been extensively investigated on one underdoped (x= 0.092) and one overdoped (x= 0.24) La 2−xSr xCuO 4 single crystals both have roughly the same quality and the same critical transition temperature T c= 26K. Large distinctions have been found for these two samples from magnetic and transport measurement. This distinction can be understood as the occurrence of an electronic macroscopic phase separation in the overdoped region. The resulting components in the phase separated overdoped state are the superconducting clusters with the same property of the underdoped region and the non-superconducting surrounding metallic phase.