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We analyze the influence of the magnetic field generated by the supercurrents (self-field) on the current density distribution by numerical simulations. The thickness of the superconducting film determines the self-field and consequently the critical current density at zero applied field. We find an equation, which derives the thickness dependence of the critical current density from its dependence on the magnetic induction. Solutions of the equation reproduce numerical simulations to great accuracy, thus enabling a quantification of the dependence of the self-field critical current density with increasing film thickness. This result is technologically relevant for the development of coated conductors with thicker superconducting layers. [ABSTRACT FROM AUTHOR]

A simple analytical expression is presented for hysteretic ac loss Q of a superconducting strip simultaneously exposed to an ac transport current I0 cos ωt and a phase-different ac magnetic field H0 cos(ωt+θ0). On the basis of the critical state model, the authors calculate Q for small current amplitude I0≤Ic, for small magnetic field amplitude H0≤Ic/2πa, and for arbitrary phase difference θ0, where Ic is the critical current and 2a is the width of the strip. The resulting expression for Q=Q(I0,H0,θ0) is a simple biquadratic function of both I0 and H0, and Q becomes maximum (minimum) when θ0=0 or π (θ0=π/2) [ABSTRACT FROM AUTHOR]