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Kaul, E. E., N. Haberkorn, and J. Guimpel. "Crystalline orientation of BiMnO3 thin films grown by rf-sputtering." Applied Surface Science 254, no. 1 (2007): 160–163.
Abstract: BiMnO3 thin films were deposited by means of rf-sputtering onto [1 0 0] oriented SrTiO3 substrates. X-ray diffraction measurements revealed epitaxial growth with [0 0 1](m) orientation in the monoclinic structure representation, equivalent to the [1 1 1](pc) direction of the pseudocubic cationic lattice. This [0 0 1](m) orientation was obtained in a wide deposition parameters range. Preliminary magnetization measurements suggest that these films do not present ferromagnetism below the bulk Curie temperature, T-c = 105 K. (C) 2007 Elsevier B.V. All rights reserved.
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Monton, C., J. Guimpel, and F. de la Cruz. "Superconducting behaviour of Nb/Co superlattices." Applied Surface Science 254, no. 1 (2007): 375–377.
Abstract: We study the superconducting and magnetic behaviour of Nb/Co superlattices, for superconducting Nb layer thickness of 44 nm and Co layer thickness less than 1 nm. In this limit no ferromagnetism is observed for Co. The superlattice behaves as independent superconducting Nb layers. We obtain the penetration depth and superconducting gap of the material, and analyze the results in terms of microscopic models and theories. (C) 2007 Elsevier B.V. All rights reserved.
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Kasama, T., M. S. Moreno, R. E. Dunin-Borkowski, S. B. Newcomb, N. Haberkorn, J. Guimpel, and P. A. Midgley. "Characterization of the magnetic properties of a GdBa2Cu3O7/La0.75Sr0.25MnO3 superlattice using off-axis electron holography." Applied Surface Science 252, no. 11 (2006): 3977–3983.
Abstract: Off-axis electron holography is used to characterize the magnetic properties of a GdBa2Cu3O7/La0.75Sr0.25MnO3 superlattice below the Curie temperature of the manganite layers, in both cross-sectional and plan-view geometry. The samples were prepared for electron microscopy using focused ion beam milling. Differences between the magnetic properties of successive manganite layers are observed in the cross-sectional sample. Magnetic ripple contrast and weakly magnetic regions are observed in plan-view geometry. Although the results may be affected by sample preparation for electron microscopy, the observed differences between the magnetic properties of the manganite layers are consistent between the different samples examined. (c) 2005 Elsevier B.V. All rights reserved.
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Haberkorn, N., G. Bridoux, E. Osquiguil, G. Nieva, and J. Guimpel. "Hall effect in a GdBa2Cu3O7-?/La0.75 Sr0.25MnO3 perovskite bilayer." Applied Surface Science 254, no. 1 SPEC. ISS. (2007): 222–224.
Abstract: We present results on the Hall coefficient RH in the normal state for a GdBa2Cu3O7-?/La0.75 Sr0.25MnO3 bilayer and a La0.75Sr0.25MnO3 film grown by dc magnetron sputtering on (1 0 0) SrTiO3. We find that the electric transport on the bilayer can be qualitatively described using a simple parallel layers model. The GdBa2Cu3O7-? layer presents a carrier density approximately equal to that reported for 7 – ? = 6.85 oxygen doping. Also we observe an unexpected presence of two Hall resistivity regimes, effects that may be associated with the internal magnetic field induced on the superconducting layer by the ferromagnetic layer.
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