Change of strength of vortex pinning in YBCO due to BaZrO3 inclusions
نویسندگان
چکیده
We probe the short-range pinning properties with the application of microwave currents at very high driving frequencies (47.7 GHz) on YBa2Cu3O7−δ films with and without sub-micrometer BaZrO3 inclusions. We explore the temperature and field ranges 60 K< T < Tc and 0< μ0H <0.8 T, with the field applied along the c-axis. The magnetic field induces a much smaller increase of the microwave resistivity, ∆ρ1(H) + i∆ρ2(H), in YBa2Cu3O7−δ/BaZrO3 with respect to pure YBa2Cu3O7−δ. ∆ρ1(H) is slightly superlinear in pure YBa2Cu3O7−δ (suggesting a possible contribution of thermal activation), but linear or sublinear in YBa2Cu3O7−δ/BaZrO3 (suggesting a possible suppression of thermal activation as a consequence of BaZrO3 inclusions). These features persist up to close to Tc. We discuss our data in terms of the ratio r = ∆X ′ s(H)/∆R ′ s(H) in the framework of the models for the microwave surface impedance in the mixed state. Large r are found in YBa2Cu3O7−δ/BaZrO3, with little field dependence. By contrast, smaller values and stronger field dependences are found in pure YBa2Cu3O7−δ. We discuss the different field dependence of the pinning constant.
منابع مشابه
High pinning performance of YBa 2 Cu 3 O 7 − x films added with Y 2 O 3 nanoparticulate defects
We report the epitaxial growth and superconducting properties of Y2O3-added YBa2Cu3Ox (YBCO) films grown on SrTiO3-buffered MgO substrates by pulsed-laser deposition using surface-modified YBCO targets. Areas of Y2O3 sectors on the YBCO target were increased to 5.44% and 9.22% of the total YBCO pellet in order to find a correlation between the Y2O3 content, morphology, and the pinning propertie...
متن کاملStrong Reduction of the Field-Dependent Microwave Surface Resistance in YBCO with BaZrO3 Inclusions
We present measurements of the magnetic field dependent microwave surface resistance in laser-ablated YBa2Cu3O7−δ films on SrTiO3 substrates. BaZrO3 crystallites were included in the films using composite targets containing BaZrO3 inclusions with mean grain size smaller than 1 μm. X-ray diffraction showed single epitaxial relationship between BaZrO3 and YBa2Cu3O7−δ. The effective surface resist...
متن کاملاثر هال در نمونه‌های ابررسانای دمای بالای YBCO آلاییده به CNT
In order to study Hall effect in pure and CNT doped YBCO polycrystalline samples, we have measured longitudinal and transverse voltages at the different magnetic field (0-9T) in the vortex state. We found a sign reversal for pure sample near 3T and double sign reversal of the Hall coefficient for CNT doped sample near 3 and 5T. It can be deduced that CNT doping caused strong flux pinning and H...
متن کاملUpward shift of the vortex solid phase in high-temperature-superconducting wires through high density nanoparticle addition
We show a simple and effective way to improve the vortex irreversibility line up to very high magnetic fields (60T) by increasing the density of second phase BaZrO3 nanoparticles. (Y0.77,Gd0.23)Ba2Cu3Oy films were grown on metal substrates with different concentration of BaZrO3 nanoparticles by the metal organic deposition method. We find that upon increase of the BaZrO3 concentration, the nano...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1985