Transport and NQR Studies of Nd_1.6-xCe_xSr_0.4CuO₄ with T^* Structure

抄録

Transport and Cu-NQR studies have been carried out for the T^*-type high temperature superconducting Cu oxide Nd_1.6-xCe_xSr_0.4CuO₄ with single layered CuO₂ planes formed by CuO₅ pyramids. No anomaly related to the static or quasi static “stripe” order has been observed in the temperature T and x dependence of the thermoelectric powers S. We have not found such kind of anomaly in the x dependence of the superconducting transition temperature T_c, either. Although the decrease of the Cu NQR intensity with decreasing T (wipeout) has been observed in this system, it can be understood by considering the loss of the itinerant nature of the electrons, which takes place in the proximity region of the metal-insulator phase boundary, and cannot be connected with the static or quasi static “stripe” order.