Superconducting and Magnetic Behavior in La 2-x Na x CuO 4

Abstract

New phases of the type La_2-xA_x^l+CUO_4-y have been prepared where A^l+ is sodium or potassium. The sodium phases are superconducting for x values from 0.2 to 0.5 at temperatures up to about 40 K. In addition, there are unusual magnetic properties below about 10 K that may be indicative of spin glass behavior. Phases of the type La_2-xK_xCuO_4-y could only be prepared with x values up to about 0.1, and these phases are not superconducting above 4.2 K