Matching in YBCO nanobridges due to surface barrier effects

Oscillatory Nernst effect in Pt|ferrite|cuprate-superconductor trilayer films

“…Furthermore, the oscillation period in our case is not determined by the sample cross-sectional area transverse to the magnetic field or the distance between the CuO 2 planes (~1 nm) in contrast to the previous studies 25–28, 30–32 . The oscillation periods in the previous papers 25–28, 30–32 were determined by , where S is the effective cross sectional area facing the magnetic field. In our Pt|LFO|YBCO samples, however, from the dimension of the YBCO layer and the distance between the CuO 2 planes, the expected period () is estimated to be 0.01–1 mT, which is much less than the observed oscillation period (~0.2 T).…”

“…S3 in Supplementary Information). Furthermore, the oscillation period in our case is not determined by the sample cross-sectional area transverse to the magnetic field or the distance between the CuO 2 planes (~1 nm) in contrast to the previous studies 25 – 28 , 30 – 32 . The oscillation periods in the previous papers 25 – 28 , 30 – 32 were determined by , where S is the effective cross sectional area facing the magnetic field.…”

“…oscillatory critical current density 25, 26 , oscillatory magnetization 27 , oscillatory mangetoresistance 28–30 , and oscillatory vibration damping 31, 32 . However, a critical difference of the present effect from the reported oscillation effects 25–32 is that the voltage oscillation (Figs 2 and 3) emerges along the Hall (Nernst) direction, while all of the known oscillations effects 25–32 are even functions with H . Also, in contrast to the oscillatory mangetoresistance 28–30 , the voltage oscillation is observed in the zero-resistivity state well below T C (Fig.…”

Josephson modulation of the critical current inYBa2Cu3O7−δfilms

“…As mentioned in the introduction, Josephson effects have been effectively observed in nanobridges, but the physics of these devices is different from that of the microbridges and the role of the boundary planes is not clear yet. 10,11,33 The good agreement between the models and the experimental measurements reported in this contribution is consistent with the suggestion that the natural boundary planes in YBCO films include weak links rows that play a major role in their superconducting properties. Although more work is needed to make this role perfectly clear, the optimization of the devices based on these films requires probably to take this aspect into account.…”

“…7 In ceramic materials, the strong sensitivity of the critical current to an applied field has been attributed to the combined Josephson behavior of the multiple weak links connecting the grains. 8,9 In YBCO films, modulation of the critical current has been obtained either in nanobridges 10,11 or by creating artificial grain boundaries with some angle either between domains with the same basal plane [12][13][14] or between domains with different basal planes. 15,16 However, no phenomenon of this type has been reported so far in YBCO thin films patterned in geometries of micrometric size including natural boundary planes only.…”