YBa<inf>2</inf>Cu<inf>3</inf>O<inf>7</inf> films grown onto SrTiO<inf>3</inf> and YSZ substrates by chemical solution deposition of trifluoroacetates

Abstract

<jats:title>Abstract</jats:title><jats:p>We report the preparation and characterization of YBa<jats:sub>2</jats:sub>Cu<jats:sub>3</jats:sub>O<jats:sub>7</jats:sub> (YBCO) films grown onto SrTiO<jats:sub>3</jats:sub> and YSZ substrates by the trifluoroacetates chemical solution deposition method and following sintering with oxygen atmosphere at 860 °C. The X-ray diffraction (XRD) reveals (00ℓ) – oriented crystallites indicating epitaxial growth of the films in the <jats:italic>c</jats:italic>-direction. Despite granular morphology and the presence of Y<jats:sub>2</jats:sub>BaCuO<jats:sub>5</jats:sub> and CuO as minor secondary phases, the technique shows the successful formation of the superconducting YBCO and preventing the formation of the unwanted BaCO<jats:sub>3</jats:sub> phase. Rocking curve measurements of the (005) reflection for the YBCO/SrTiO<jats:sub>3</jats:sub> was fitted with one Gaussian function with full width at the half maximum (FWHM) of 0.44° confirming that it consists of YBCO crystallites with different texture. For the sample grown on YSZ, the rocking curve was fitted with two Gaussian functions, one corresponding to the YBCO layer (FWHM = 0.4°) and another to the substrate (FWHM = 0.3°). The magnetic measurements taken in zero field cooling and field cooling modes confirm the formation of the superconducting YBCO with critical temperatures (<jats:italic>T</jats:italic><jats:sub>C</jats:sub>) 91.8 and 85.7 K for the samples grown onto YSZ and SrTiO<jats:sub>3</jats:sub>, respectively. The critical current density (<jats:italic>J</jats:italic><jats:sub>C</jats:sub>) curves indirectly calculated by using the Bean´s model from the <jats:italic>M</jats:italic>(<jats:italic>T</jats:italic>) loops were <jats:italic>J</jats:italic><jats:sub>C</jats:sub> ~ 10<jats:sup>9</jats:sup> A/cm<jats:sup>2</jats:sup> for the sample deposited onto YSZ and <jats:italic>J</jats:italic><jats:sub>C</jats:sub> ~ 10<jats:sup>7</jats:sup>A/cm<jats:sup>2</jats:sup> for the YBCO deposited onto SrTiO<jats:sub>3</jats:sub>. Overall, the difference in <jats:italic>T</jats:italic><jats:sub>C</jats:sub> and <jats:italic>J</jats:italic><jats:sub>C</jats:sub> values between both samples could be related to their difference in oxygen content, porosity, hole concentration per Cu ion and the presence of secondary phases.</jats:p>