Magnetoresistivity of thin YBa2Cu3O7−δ films on sapphire substrate

Abstract

Magnetoresistivity of YBa2Cu3O7− films with thicknesses between 7 and 100 nm deposited on CeO2 and PrBa2Cu3O7− buffer layers on sapphire substrate has been measured to analyze the temperature dependence of the second critical magnetic field Bc2. To define Bc2, the mean-field transition temperature Tc was evaluated by fitting the resistive transition in zero magnetic field with the fluctuation conductivity theory of Aslamazov and Larkin. At T → Tc the Bc2(T) dependence shows a crossover from downturn to upturn curvature with the increase in film thickness. AbstractMagnetoresistivity of YBa 2 Cu 3 O 7- ultra-thin films with thicknesses between 7 and 100 nm deposited on sapphire substrate using CeO 2 and PrBa 2 Cu 3 O 7- buffer layers has been measured to analyze temperature dependence of the second critical magnetic field B c2 . B c2 was determined using T c values obtained by fitting of resistivity vs. temperature data with the fluctuation conductivity theory of Aslamazov-Larkin. At T  T c the B c2 (T) dependence shows a crossover from downturn to upturn curvature with the increase of the YBCO film thickness.

Transport properties of ultrathin YBa2Cu3O7−δ nanowires: A route to single-photon detection

“…In Figure 5 we have plotted (red circles) the T 0 C extracted by our YBCO films -bare films above t = 10 nm and Au capped films below t = 10 nm -as a function of the thickness. As discussed earlier the T 0 C slightly dethickness (nm) Terashima et al [12] Chan et al [14] Cieplak et al [13] Savvides et al [43] Tang et al [39] Probst et al [45] Probst et al [53] This work FIG. 5: Zero resistance critical temperature T 0 C of our capped and bare YBCO films versus their thickness (red circles).…”

“…Transport properties of the ultrathin YBCO films have been studied by resistance vs temperature R(T ) measurements. For ultrathin YBCO films, when grown on substrates with a large mismatch (without a PBCO seed layer), a strong reduction of the zero resistance temperature, T 0 C , has been reported [45]. Here we show instead that the T 0 C of our films is higher than the liquid nitrogen temperature down to thicknesses of 10 nm.…”

“…In particular, open symbols show results achieved on YBCO films sandwiched between two PBCO layers by Matsuda et al [12,52], Chan et al [14], Cieplak et al [13], Tang et al [39], and Probst et al [53]. Filled symbols show instead results achieved on YBCO films, not embedded between two PBCO layers, by Terashima et al [12], Savvides et al [43], and Probst et al [45].…”

“…In Figure 5 we have plotted (red circles) the T 0 C extracted by our YBCO films -bare films above t = 10 nm and Au capped films below t = 10 nm -as a function of the thickness. As discussed earlier the T 0 C slightly dethickness (nm) Terashima et al [12] Chan et al [14] Cieplak et al [13] Savvides et al [43] Tang et al [39] Probst et al [45] Probst et al [53] This work [12,52], Chan et al [14], Cieplak et al [13], Tang et al [39], and Probst et al [53]. Filled symbols show instead results achieved on YBCO films, not embedded between two PBCO layers, by Terashima et al [12], Savvides et al [43], and Probst et al [45].…”