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We have studied the vortex-related phase transition in a number of YBCO thin films that have in-plane anisotropy due to the c-axis lying at an angle to the substrate normal. The critical parameters Tt , z, and ν have been extracted from the scaling of dc I-V measurements made along the two principal transport directions in magnetic fields up to 1 tesla. The dependence of Tt upon the direction of the transport current in some classes of film and the very high z values cast doubt upon the established interpretation based simply upon a vortex liquid–vortex glass phase transition. [ABSTRACT FROM AUTHOR]

We have identified a Mn-rich layer on the surface on (Ga,Mn)As thin films which significantly influences soft x-ray absorption measurements. The Mn L3,3 x-ray absorption spectra of the untreated films show a strong multiplet structure, consistent with earlier observations and characteristic of MnO. After removal of the surface layer, the multiplet structure is less pronounced and the spectrum is shifted to ∼0.5 eV lower photon energy. Comparison with calculated spectra imply a localized Mn ground state for the untreated sample and a hybridized ground state after etching. In addition, a large x-ray magnetic circular dichroism is observed at the Mn L3,2 edge in the etched film. These results may explain several peculiarities of previously reported x-ray absorption studies from (Ga,Mn)As. [ABSTRACT FROM AUTHOR]

Comments on the interest in fabricating structures including microbridges and vortex flow devices from high Tc, thin films with high in-plane electrical anistropy. Study of two types of film; Other information on the film.

There is much current interest in fabricating structures including microbridges and vortex flow devices from high Tc thin films with high in-plane electrical anisotropy. Two types of film have been studied, films grown on 10° vieinaliy cut SrTiO3, and (013)/(103) oriented films grown on (110) SrTiO3 substrates in a two-temperature growth process. The 10° films have a normal state anisotropy of 3-6 (100K) dependent on film thickness . The l0Onm (013)/(103) films have a normal state anisotropy of 23 (1OOK). We report wide ranging I-V measurements taken over a range of temperatures and applied magnetic fields for both the normal and superconductings states for these films. This data is used to investigate the anisotropy below Tc both in the linear (flux-flow) regime and in the non-linear (iireversibility) regime at lower temperatures and higher currents. [ABSTRACT FROM PUBLISHER]

(Ga,Mn)As is at the forefront of spintronics research exploring the synergy of ferromagnetism with the physics and the technology of semiconductors. However, the electronic structure of this model spintronics material has been debated and the systematic and reproducible control of the basic micromagnetic parameters and semiconducting doping trends has not been established. Here we show that seemingly small departures from the individually optimized synthesis protocols yield non-systematic doping trends, extrinsic charge and moment compensation, and inhomogeneities that conceal intrinsic properties of (Ga,Mn)As. On the other hand, we demonstrate reproducible, well controlled and microscopically understood semiconducting doping trends and micromagnetic parameters in our series of carefully optimized epilayers. Hand-in-hand with the optimization of the material synthesis, we have developed experimental capabilities based on the magneto-optical pump-and-probe method that allowed us to simultaneously determine the magnetic anisotropy, Gilbert damping and spin stiffness constants from one consistent set of measured data. [ABSTRACT FROM AUTHOR]