Magnetic and superconducting properties of Nd_1.85Ce_0.15CuO₄

Abstract

Magnetic investigations of the electron-doped superconductor Nd2-xCexCuO4 (with nominal composition x=0.15) are reported. In a low external field (5 G) the normal state susceptibility obeys the Curie-Weiss law but in higher fields a deviation from this behaviour is observed at T approximately=40 K. From the high-temperature data the value of the Curie temperature theta =-70 K is obtained, indicating antiferromagnetic interactions. Hysteresis measurements give the critical current density of jc=2.3*102 A cm-2 in a field of 30 G. From the logarithmic time dependence of the thermoremanent magnetisation we estimate an activation energy of Uo=0.05 eV for thermally induced flux creep.