Preparation, scaling behavior of activation energy, Hall effect, and flux-flow anisotropy of (Hg_0.9Re_0.1)Ba ₂CaCu₂O _6+δ HTS thin films

We have prepared fully textured (Hg_0.9Re_0.1)Ba ₂CaCu₂O_6+δ (HgRe-1212) thin films by pulsed laser deposition (PLD) and post-annealing. The films exhibit sharp superconducting transitions at T_c = 124 K with transition width ΔT_c ≃ 2 K. Conditions for reproducible film preparation have been found. The resistive transitions have been investigated in magnetic fields up to 8 T (parallel to the c-axis) and 10 T (perpendicular to the c-axis). We have determined the activation energy of thermally activated flux-motion for both magnetic field orientations. The Hall resistivity (ρ_xy) of HgRe-1212 superconductor thin films has been measured in the ab-plane at 8 T. In the mixed state a power-law behavior is observed, where ρ_xy scales to a power-law function of ρ _xx:ρ_xy = Aρ_xx^β, with β = 1.4 ± 0.1. Above 130 K the T² dependence of the cotangent of the Hall angle is observed. At different temperatures magnetization loops were measured with a magnetic field applied normal to the film in a SQUID magnetometer and the corresponding critical current densities J_c were calculated. Under variation of the angle θ between the field direction and the c-axis of the film the anisotropic properties of the vortex state and the depinning field B_dp(θ) have been studied. The measured angular dependence B_dp(θ) shows a cusp for θ = 90°. The films exhibit a rather low critical field anisotropy of 7.7.