| 1. |
- Fors, Rickard, et al.
(författare)
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Sol-gel derived versus pulsed laser deposited epitaxial La0.67Ca0.33MnO3 films : structure, transport and effects of post-annealing
- 2004
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 467:02-jan, s. 112-116:467, s. 112-116
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Tidskriftsartikel (refereegranskat)abstract
- Epitaxial La0.67Ca0.33MnO3 films have been prepared on LaAlO3 crystals by pulsed laser deposition (PLD) and by a novel all-alkoxide sol-gel technique. Different out-of-plane lattice parameters are found for the as-prepared films, and scanning electron microscopy shows a more porous structure for sol-gel films as compared to PLD films. These differences are largely removed by post annealing at 1000 degreesC. Transport measurements show maximum temperature coefficient of resistivity of 8.2% K-1 at 258 K (PLD) and 6.1% K-1 at 241 K (sol-gel) and colossal magnetoresistance at 560 kA/m of 35% at 263 K (PLD) and 32% at 246 K (sol-gel).
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| 2. |
- Grishin, Alexander M., et al.
(författare)
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Green and blue magneto-optical photonic crystals
- 2012
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 520:9, s. 3647-3650
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Tidskriftsartikel (refereegranskat)abstract
- A series of one-dimensional heteroepitaxial all-garnet magneto-optical photonic crystals (MOPCs) were pulsed laser deposited to operate at 550 and 470 nm wavelength. We explored the concept of blue shift of the optical absorption edge of ferric ions by substituting Fe with Ga on the tetrahedral sites as well as Bi and Y, respectively, with Ca and Ce at the dodecahedral coordinated positions. 17-layered [Y2Ce1Fe5O12/Gd3Ga5O12] MOPC with a total thickness of 968 nm demonstrates superior magneto-optical performance: Faraday rotation theta(Fmax) = + 2.0 degrees and transmittance as high as 0.35 at the resonance wavelength of 470 nm.
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| 3. |
- Johansson, Petter, et al.
(författare)
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Comparison of Bi3Fe5O12 film giant Faraday rotators grown on (111) and (001) Gd3Ga5O12 single crystals
- 2006
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 515:2, s. 477-480
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Tidskriftsartikel (refereegranskat)abstract
- Bismuth iron garnet (Bi3Fe5O12, BIG) epitaxial thin films were grown on single crystal (Gd3Ga5O12, GGG) (111) and (001) substrates by rf-magnetron sputtering technique. Processing parameters have been optimized to obtain high deposition rate (2.74 mu m/h) and the surface rms roughness less than 10 nm. X-ray diffraction reveals films epitaxial quality: exclusive (111) or (00 1) orientation with narrow rocking curves and strong in-plane texture. Films possess low optical loss and magneto-optical Faraday rotation (FR) as high as 5 deg/mu m at 677 nm wavelength. Comparative analysis of films grown on (111) and (001) substrates clearly shows significant superiority of BIG/GGG(001) film. For this film, the coercive field similar to 100 Oe appears to be 2.5 times lower while the optical transmission to be 10% higher than that for BIG/GGG(111) film. Enhanced magneto-optical performance of BIG/GGG(001) films relies upon better accommodation of the film-to-substrate mismatch strain through the tetragonal BIG lattice distortions compared to the rhombohedral one in BIG/GGG(111) films.
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| 4. |
- Razdolski, I. E., et al.
(författare)
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Magneto-optical switching in nonlinear all-garnet magnetophotonic crystals
- 2011
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 519:16, s. 5600-5602
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic field control over the optical switching is demonstrated for a nonlinear all-garnet magnetophotonic crystal with a microcavity (MC) layer possessing both third-order Kerr nonlinearity and magnetooptical activity. A significant enhancement of the effective refractive index of the microcavity layer is observed, that results in the light-induced spectral shift of the MC mode of 2 nm. It is shown that application of the external magnetic field leads to an increase of switching contrast by a factor of two. Possible mechanisms of photorefractive effect involved in the optical switching in all-garnet magnetophotonic crystals are discussed.
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| 5. |
- Velichko, A., et al.
(författare)
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Memory resistive switching in CeO2-based film microstructures patterned by a focused ion beam
- 2014
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 556, s. 520-524
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Tidskriftsartikel (refereegranskat)abstract
- Heteroepitaxial CeO2 (80 nm)/La0.5Sr0.5CoO3 (500 nm) film structure has been pulsed laser deposited on a sapphire substrate. The Ag/CeO2 microjunctions patterned by a focused ion beam on a La0.5Sr0.5CoO3 film exhibit reproducible reversible switching between a high resistance state (OFF) with insulating properties and a semiconducting or metallic low resistance state (ON) with resistance ratios up to 10(4). The influence of micro-scaling and defects formed at the cell boundaries during etching on its electrical characteristics has been analyzed. The appearance of a switching channel at the moment of the electrical forming, responsible for the memory effect, has been proved, along with a mechanism of a self-healing electrical breakdown.
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| 6. |
- Östling, Mikael, et al.
(författare)
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Ferroelectric thin films on silicon carbide for next-generation nonvolatile memory and sensor devices
- 2004
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 469-70, s. 444-449
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide semiconductor technology has emerged as a very good candidate to replace traditional Si devices in special applications such as low loss power switching and high temperature electronics. Ferroelectric thin films exhibit interesting properties for use in semiconductor technology due to the spontaneous polarization which can be switched by an externally applied electric field, and thus are attractive for nonvolatile memory and sensor applications. In this work, the successful realization of ferroelectric thin films in SiC devices is described. The first experimental prototype devices are presented and discussed: A novel integration technique of junction metal-oxide-semiconductor field effect transistors (JMOSFETs) and nonvolatile FETs (NVFETs) on a single 4H-SiC substrate is presented. A constant current control device is based on the SiC JMOSFET. The drain current is effectively controlled and kept constant by a buried junction gate. A new high temperature SiC NVFET with a similar temperature stable current drive is also demonstrated. The nonvolatile memory device, based on the ferroelectric gate stack, was shown to operate up to 300 C with memory effect retained up to 200degreesC.
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