Broadband dielectric and IR pyroelectric response of amorphous Y-Ba-Cu-O oxygen depleted thin films

• Published in: IOP conference series. Materials Science and Engineering 2012-01, Vol.41 (1), p.12013-4
• Main Authors: Gensbittel, A, Dégardin, A F, Dubrunfaut, O, Kulsreshath, M K, Jagtap, V S, Kreisler, A J
• Format: Article
• Language: English
• Subjects: AMORPHOUS STRUCTURE; BOUNDARIES; Broadband; Detectors; Dielectric properties; Dielectric relaxation; Film thickness; Frequency ranges; Grain boundaries; High temperature; INFRARED RAYS; INSULATION (ELECTRICAL); Materials science; OXYGEN; SUPERCONDUCTORS; Temperature; Thickness measurement; THIN FILMS; YBCO superconductors; Yttrium barium copper oxide; YTTRIUM OXIDE
• ISSN: 1757-8981; 1757-899X
• DOI: 10.1088/1757-899X/41/1/012013

We report on the study of dielectric properties of amorphous semiconducting YBa2Cu3O6+x (x < 0.5, YBCO) thin films with two different thicknesses measured in a broad frequency range (from 40 Hz to 2 GHz) and in the 210 to 430 K temperature range, using a coaxial discontinuity technique. At all temperatures, dielectric permittivity and conductivity spectra exhibit typical features of dielectric relaxation processes. A first relaxation at low frequency (300 Hz – 2 kHz), observed only at high temperature, might be attributed to interfacial effects. Grain boundaries of the YBCO thin films could explain the second relaxation observed at higher frequency (800 Hz – 660 kHz). The higher relaxation frequencies increase with temperature and film thickness and follow a thermally activated behavior of the Arrhenius-type. Application to IR detection with a film deposited on silicon has been targeted: the observed pyroelectric behavior of the detector exhibits a fast response in the μs range.