Electrical and thermal transport properties of the electron-doped cuprate Sm2−xCexCuO4−y system

Abstract

Electrical and thermal transport measurements were performed on thin films of the electron-doped superconductor Sm2−xCexCuO4−y (x = 0.13 − 0.19) in order to study the evolving nature of the charge carriers from the under-doped to over-doped regime. A temperature versus cerium content (T − x) phase diagram has been constructed from the electrical transport measurements, yielding a superconducting region similar to that found for other electron-doped superconductors. Thermopower measurements show a dramatic change from the underdoped region (x < 0.15) to the overdoped region (x > 0.15). Application of the Fisher–Fisher–Huse (FFH) vortex glass scaling model to the magnetoresistance data was found to be insufficient to describe the data in the region of the vortex-solid to vortex-liquid transition. It was found instead that the modified vortex glass scaling model of Rydh, Rapp, and Anderson provided a good description of the data, indicating the importance of the applied field on the pinning landscape. A magnetic field versus temperature (H − T) phase diagram has also been constructed for the films with , displaying the evolution of the vortex glass melting lines Hg(T) across the superconducting regime.