Anisotropic Josephson effect in all (103)-oriented YBa2Cu3O7−δ /PrBa2Cu3O7−δ′/YBa2Cu3O7−δ junctions

Abstract

We report a demonstration of the anisotropic Josephson effect in all (103)-oriented junctions consisting of YBa2Cu3O7−δ /PrBa2Cu3O7−δ′/YBa2Cu3O7−δ film sandwiches. The junction shows a resistively shunted junction-like current-voltage characteristics with hysteresis and clear Shapiro steps under the microwave radiation. Depending on the direction of external magnetic field H, the junction exhibits anisotropic Fraunhofer interference patterns with different critical magnetic fields Hc0 and periods in the oscillation of critical current. The agreement between experimental and expected values by the Owen–Scalapino analysis for anisotropic Hc0 confirms that this anisotropic property comes from the anisotropy in the magnetic penetration depth of (103)-oriented YBaCuO films.

Disorder in two-dimensional Josephson junctions

“…These predictions can serve to identify these phases. We show that a transition between the glass phase and the coexistence phase can occur well below the critical temperature T c of the bulk, a result which may account for the experimental data on trilayer junctions [1][2][3][4][5].…”

“…Experimental studies of trilayer junctions like [ [1] with area of 50µm 2 a zero resistance state was achieved only below 50K, although the Y Ba 2 Cu 3 O x layers were superconducting already at T c ≈ 85K. More recent data on similar YBCO junctions [3][4][5] with junction areas of 10 2 − 10 4 µm 2 show a measurable I c only at 20 − 60K below T c of the superconducting layers. An even larger junction [6] of area ≈ 10 5 µm 2 shows a well defined gap structure in the I − V curve while a critical current is not observed.…”

Quasiparticle Tunneling Properties of PlanarYBa2Cu3O7−δCucolo1, Leo2, Nigro3 et al. 1996Phys. Rev. Lett.361160View full textAdd to dashboardCite

“…In particular, YBa 2 Cu 3 O 72d ͞PrBa 2 Cu 3 O 72d 0 ͞YBa 2 Cu 3 O 72d junctions have been investigated in detail by using a-axis oriented [1][2][3] and, more recently, (103)-oriented films [4].…”

Tunneling and hopping conduction via localized states in thinPrBa2Cu3Yoshida1, Nagano2 1997Phys. Rev. B250140View full textAdd to dashboardCite

“…Although a nearly ideal Josephson effect in YBCO/PBCO/YBCO junctions has been demonstrated by several groups, [2][3][4][5][6][7] no conventional theory based on either tunneling or the proximity effect has given a satisfactory explanation for the mechanism of Josephson coupling through the considerably thick PBCO barrier layers amounting to several tens of nm. Recently, resonant tunneling of Cooper pairs through localized states with long localization length has been proposed as a possible origin of Josephson coupling in these junctions.…”