Effect of the misalignment between the applied and internal magnetic fields on the critical currents of “tilted coated conductors”

Abstract

We present angular-dependent measurements of the critical current density (Jc) of a YBa2Cu3O7 film grown on tilted buffered Ion-Beam-Assisted-Deposition MgO metal tapes. We compare samples with the current parallel and perpendicular to the tape’s direction. In samples with the current parallel to the tape, we observe an asymmetric angular dependence of Jc and a shift of the ab-planes maxima position with the magnetic field strength. The shift is a result of the misalignment between the applied and internal magnetic fields. The misalignment effect takes place at fields lower than 3T at T=75.5K. For samples with the current perpendicular to the tape, we find an overall reduced value of Jc, the angular behavior is symmetrical, and no shift in the maxima position as a function of the magnetic field is observed. These results indicate that the effect of misalignment between the applied and internal magnetic fields must be taken into account when studying the angular dependence of Jc.

Critical Current Densities of MOCVD Tapes for Different Current Directions

“…, consistent with what has been reported in [14]. This corresponds to a reduced field of , which is very similar to the value of found in [15].…”

“…The maxima move from the -planes to the defect planes and then further towards the -axis, which corresponds to the "anisotropy-dominated" case described in [15]. Note that the peak found at film normal at intermediate fields discussed above moves in the opposite direction, confirming that in one sample the "anisotropy-dominated" and the "geometry-dominated" situation can be observed at the same time [14]. It needs to be pointed out that the peak shifts are directly related to the reduced symmetry of vicinal samples (enhanced by the tilt of the precipitate planes) and that they would not be observed in -axis oriented films.…”

“…This behavior has again been reported previously [4], [5], [14] and was explained by an offset between the direction of the applied field and the magnetic flux density in the sample, given by the orientation of the vortices [15]. The maxima move from the -planes to the defect planes and then further towards the -axis, which corresponds to the "anisotropy-dominated" case described in [15].…”

Ultrafine Multilayers of Complex Metal Oxide Films

“…2-5°) in the alignment of the IBAD MgO template relative to the surface normal. [27] This asymmetry is washed out in higher fields as shown in Figure 3c. As the applied field is rotated away from the ab plane of the film, the I c of the mixed RE film falls off faster compared to the pure Y123 film, while the I c of the ultrafine multilayer film again has a slower decay and significantly improved properties for H ʈ c (H = 0°).…”

Influence of growth temperature on the vortex pinning properties of pulsed laser deposited YBa2Cu3O7−x thin films

“…The ab planes are highlighted with white dashed arrows, from which it can be seen that the ab planes are not straight but tilted as much as 2°-5°from the substrate. This ab plane tilting causes an angular dispersion of the stacking faults and antiphase boundaries about the nominal film plane direction, which can produce an irregular angular dependence of J c in magnetic fields, 33,34 as will also appear in Fig. 5.…”