Oxygen content dependence of the EPR line shape in GdBa2Cu3O7−y single crystal

Abstract

X-band electron paramagnetic resonance (EPR) spectra of a GdBa2Cu307_y single crystal were obtained at room temperature before and after reducing its oxygen content by annealing. Before annealing, the sample exhibited superconductivity at T c ~ 90 K; the EPR line was asymmetrical and was described with a Dysonian shape because of the skin effect. After annealing, superconductivity was not observed; the EPR line, less affected by the skin effect, was symmetrical and more intense, approximately described with a Lorentzian shape.

Electron Spin Resonance and Atomic Force Microscopy Study on Gadolinium Doped Ceria

“…It is interesting to investigate why the best fits of the ESR line profile were those obtained by a Dysonian function and why the last fits better at higher values ( Figure 2). In most cases, a Dysonian line-shape appears when a sample becomes an electronic conductor [24][25][26]. However, it is well known that Ce 1−x Gd x O 2−x/2 solid solutions have negligible electronic conductivity, apart from pure CeO 2 and slightly Gd-doped compounds when annealed in reducing conditions [2,11,27,28].…”