| 51. |
- Wang, Xin, et al.
(författare)
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Composition, structure, and dielectric tunability of epitaxial SrTiO3 thin films grown by radio frequency magnetron sputtering
- 1999
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Institute of Physics (AIP). - 0734-2101 .- 1520-8559. ; 17:2, s. 564-570
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial (001) oriented SrTiO3 films have been deposited on LaAlO3(001) substrates by off-axis radio frequency magnetron sputtering in Ar:O-2 gas mixtures at substrate temperatures ranging from 650 to 850 degrees C. For the deposition conditions used, stoichiometric targets yielded 20% Sr-deficient films, whereas Sr-enriched targets (Sr1.1TiO0.9O3.0) resulted in stoichiometric films. The Sr-deficient films had a mosaic structure and a larger lattice parameter in comparison to bulk SrTiO3. The stoichiometric films on the other hand had a much higher crystalline quality in the as-deposited condition. The mosaicity of the latter films was primarily limited by the crystalline quality of the LaAlO3 substrates. The lattice parameters of the stoichiometric films were also smaller than the Sr-deficient ones and closer to the bulk value. The dielectric properties of the stoichiometric films were superior to the Sr-deficient films. For films with a thickness of similar to 300 nm, the typical dielectric constants as measured at similar to 77 K and I MHz were determined to be 820 and 500, for the stoichiometric and Sr-deficient films, respectively. Also the capacitance change, as a direct current bias voltage was applied to an interdigital capacitor, was higher for the stoichiometric film, 27.3% as compared to 8.6% when applying a bias of 300 V at 77 K. We also demonstrate the effectiveness of thermal annealing in improving both crystalline quality and dielectric properties, especially for the Sr-deficient films. (C) 1999 American Vacuum Society. [S0734-2101(99)010002-7].
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| 52. |
- Westerberg, Lars, et al.
(författare)
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Hydrogen content and outgassing of air-baked and vacuum-fired stainless steel
- 1997
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Ingår i: VACUUM. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0042-207X. ; 48:7-9, s. 771-773
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The hydrogen content of stainless steel samples, treated by 400 degrees C heat treatment for 2, 4, 8, 16 and 24 h in ambient air, was determined by the H-1(N-15,alpha gamma)C-12 nuclear resonance reaction, and a standard extraction method Two reference sa
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| 53. |
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| 54. |
- Östman, Erik, et al.
(författare)
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Hysteresis-free switching between vortex and collinear magnetic states
- 2014
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 16, s. 053002-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a lossless switching between vortex and collinear magnetic states in circular FePd disks arranged in a square lattice. Above a bifurcation temperature (Te) we show that thermal fluctuations are enough to facilitate flipping between the two distinctly different magnetic states. We find that the temperature dependence of the vortex annihilation and nucleation fields can be described by a simple power law relating them to the saturation magnetization.
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| 55. |
- Östman, Erik, et al.
(författare)
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Interaction modifiers in artificial spin ices
- 2018
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Ingår i: Nature Physics. - : NATURE PUBLISHING GROUP. - 1745-2473 .- 1745-2481. ; 14:4, s. 375-379
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Tidskriftsartikel (refereegranskat)abstract
- The modification of geometry and interactions in two-dimensional magnetic nanosystems has enabled a range of studies addressing the magnetic order(1-6), collective low-energy dynamics(7,8) and emergent magnetic properties(5,9,10) in, for example, artificial spin-ice structures. The common denominator of all these investigations is the use of Ising-like mesospins as building blocks, in the form of elongated magnetic islands. Here, we introduce a new approach: single interaction modifiers, using slave mesospins in the form of discs, within which the mesospin is free to rotate in the disc plane(11). We show that by placing these on the vertices of square artificial spin-ice arrays and varying their diameter, it is possible to tailor the strength and the ratio of the interaction energies. We demonstrate the existence of degenerate ice-rule-obeying states in square artificial spin-ice structures, enabling the exploration of thermal dynamics in a spin-liquid manifold. Furthermore, we even observe the emergence of flux lattices on larger length scales, when the energy landscape of the vertices is reversed. The work highlights the potential of a design strategy for two-dimensional magnetic nano-architectures, through which mixed dimensionality of mesospins can be used to promote thermally emergent mesoscale magnetic states.
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| 56. |
- Östman, Erik, et al.
(författare)
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Ising-like behaviour of mesoscopic magnetic chains
- 2018
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 30:36
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate an experimental realization of the short range magnetic order in a one-dimensional Ising chain using fabricated mesospins. We confirm an excellent agreement between the experimental findings and simulations obtained using the original Ising model. In particular, we are able to show that the thermal behaviour of the mesoscopic Ising chain dominates over the thermal behaviour of the individual mesospins themselves, confirming that fabricated mesospins can be viewed as artificial magnetic atoms.
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