Large distinctions between underdoped and overdoped La2-xSrxCuO4 single crystals as observed from magnetic and transport measurement: A possible evidence for macroscopic phase separation in overdoped high temperature superconductors

Magnetic and DC transport properties have been extensively investigated on one underdoped (x = 0.092) and one overdoped( x = 0.24) La2-xSrxCuO4 single crystals both have roughly the same quality and the same critical transiti on temperature T-c= 26 K. Large distinctions have been found for these two samples from magnetic and transport measurement. This distinction can be un derstood as the occurrence of an electronic macroscopic phase separation in the overdoped region. The resulting components in the phase separated over doped state are the superconducting clusters with the same property of the underdoped region and the nonsuperconducting surrounding metallic phase.