Magnetic-field-induced localization in the normal state of superconducting La2-xSrxCuO4

Magnetoresistance measurements of highly underdoped superconducting La2-xSrxCuO4 films with x = 0.051 and x = 0.048, performed in dc magnetic fields up to 20 T and at temperatures down to 40 mK, reveal a magnetic-field-induced transition from weak to strong localization in the normal state. The normal-state conductances per CuO2 plane, measured at different fields in a single specimen, are found to collapse to one curve with the use of a single scaling parameter that is inversely proportional to the localization length. The scaling parameter extrapolates to zero near zero field and possibly at a finite field, suggesting that in the zero-field limit the electronic states may be extended.