Dimpling in critical current density vs. magnetic field angle in YBa2Cu3O7 films irradiated with 3-MeV gold ions

Abstract

Magnetic-field-angle θ dependence of critical current density Jc was measured in YBa2Cu3O7 films irradiated with 3-MeV gold ions. Such films were recently found to show large pinning force arising from point-like irradiation defects. A dimpled line-shape of Jc(θ) and its variation with magnetic field strength were revealed that could be well described by a simple model based on flux-lattice shear and Blatter scaling. Our results strongly suggest that vortex elasticity and electron-mass anisotropy coordinately produce the characteristic Jc anisotropy, called “shoulders,” in cuprate and iron-pnictide films.

Tuning nanoparticle size for enhanced functionality in perovskite thin films deposited by metal organic deposition

“…Several models have been proposed to explain J c (T, H, θ) in cuprate and pnictide superconductors with strong pinning NPs or NRs. 21,24,[50][51][52][53][54][55][56][57][58][59] Although the influence of creep Tuning NP size for enhanced functionality M Miura et al on J c for these superconductors has been known for a long time, 49,60 only a few attempts have been made to link the pinning improvements to J c and S. 60,61 To calculate the temperature, magnetic field and field angle dependence of J c (J c;calc: ), we use J c;calc: T; H; y ð Þ¼ J c0 T; H; y ð Þ1 À Sln t=t 0 ð Þ ð Þ , where t 0 is the effective attempt time, J c0 is the creep-free J c and S is the experimentally obtained flux creep rate.…”

Influence of nano-particle diameter on superconducting properties in BaMO3(M = Sn, Hf)/YBa2Cu3O quasi-multilayered films

“…Then, it is speculated that the diameter of BSO nano-particles in the BSO(1,100)750 would be less than 2n at the 77.3 K, but larger than 2n at the 65 K, where the coherence length at 65 K is shorter than that at 77.3 K. Another possible reason is that the BSO nano-particles would be more aligned along the c-axis for the 770°C film. Recently, a similar J c peak has been also reported in YBCO thin films irradiated with 3 MeV Au ions [13], where the pointlike defects were randomly distributed in the films. The irradiated YBCO, however, shows that the angular curve of J c dimples locally at h = 0°with increasing magnetic field.…”

Comment on “Dimpling in critical current density vs. magnetic field angle in YBa2Cu3O7 films irradiated with 3-MeV gold ions” [J. Appl. Phys. 114, 233911 (2013)]

“…The B 0 or B irr values from the fit also differ from those in Ref. 1. In our analysis, the fit parameters of Fig.…”

“…In a recent paper, Matsui et al 1 suggest electronic mass anisotropy plays a dominant role in creating the "shoulder" type characteristics seen in the J c (h) dependence of pinning-enhanced YBa 2 C 3 O 7 (YBCO) and BaFe 2 As 2 films.…”

“…Then for each angle we could find a value B irr (h) and scale the data to form F p (B,h) ¼ F 0 (B/B irr (h)) m (1 À B/B irr (h)) n ; this is effectively the proposed scaling law of Ref. 1. If B irr (h) can be characterised by N parameters, e.g., using the electronic mass anisotropy expression, N ¼ 2, then the entire F p (B,h) space is then fully characterised by 3 þ N ¼ 5 parameters.…”