The Experts below are selected from a list of 114921 Experts worldwide ranked by ideXlab platform
J. A. C. Bland - One of the best experts on this subject based on the ideXlab platform.
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roughness induced variation of Magnetic Anisotropy in ultrathin epitaxial films the undulating limit
Physical Review B, 2007Co-Authors: C A F Vaz, S J Steinmuller, J. A. C. BlandAbstract:We identify an extra Magnetic Anisotropy contribution due to roughness in ultrathin single crystalline Magnetic films grown on randomly corrugated surfaces. In this picture, the magnetization follows the roughness profile leading to a tilting of the magnetization away from the easy magnetization axis and hence to a modification of the Magnetic Anisotropy. This ``undulating'' Magnetic state competes with the alternative possibility of uniform in-plane magnetization, which carries a cost in magnetostatic energy due to surface charges. The limits of validity of the model presented are discussed in terms of the roughness amplitude, correlation length, film thickness, and the intrinsic Magnetic parameters of the film.
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anisotropic lattice relaxation and uniaxial Magnetic Anisotropy in fe inas 100 4 2
Physical Review B, 2000Co-Authors: D. J. Freeland, M. Tselepi, J. A. C. BlandAbstract:The Magnetic Anisotropy and the lattice relaxation of epitaxial Fe films grown on InAs(100)-4×2 at room temperature have been studied using in situ magneto-optical Kerr effect and reflection high-energy electron diffraction. The experimental results demonstrate that the symmetry breaking associated with the intrinsic atomic scale structure of the reconstructed semiconductor surface induces an in-plane anisotropic lattice relaxation and an in-plane uniaxial Magnetic Anisotropy in the ultrathin region. We propose that this is a general phenomenon in ferroMagnetic/semiconductor heterostructures. © 2000 The American Physical Society.
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uniaxial Magnetic Anisotropy of epitaxial fe films on inas 100 4 2 and gaas 100 4 2
Journal of Applied Physics, 2000Co-Authors: D. J. Freeland, M. Tselepi, J. A. C. BlandAbstract:The evolution of the uniaxial Magnetic Anisotropy of ultrathin epitaxial Fe films grown on InAs(100)-4×2 and GaAs(100)-4×2 has been studied in situ by means of the magneto-optical Kerr effect. In Fe/InAs(100)-4×2, the uniaxial Magnetic Anisotropy easy axis direction along [011] was found to be rotated 90° compared with that of Fe/GaAs(100)-4×2 along [011]. Real-time reflection high energy electron diffraction measurements of Fe/InAs(100)-4×2 show that the lattice constant of the epitaxial Fe films relaxes remarkedly faster along the [011] direction than along the [011] direction in the same thickness range where the uniaxial Magnetic Anisotropy occurs. These results suggest that the symmetry-breaking atomic scale structure of the reconstructed semiconductor surface gives rise to the uniaxial Magnetic Anisotropy in a ferroMagnetic metal/semiconductor heterostructure via surface magneto-elastic interactions.
Y. Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Voltage-induced perpendicular Magnetic Anisotropy change in Magnetic tunnel junctions
Applied Physics Letters, 2010Co-Authors: Tatsuo Nozaki, TAKAO SHINJO, Yoichi Shiota, M Shiraishi, Y. SuzukiAbstract:A voltage-induced perpendicular Magnetic Anisotropy change in an ultrathin FeCo layer was observed in an epitaxialMagnetic tunnel junction(MTJ) structure. A spin-transfer induced ferroMagnetic resonance measurement technique was used under various bias voltage applications to evaluate the Anisotropy change. From the peak frequency shifts, we could estimate that a surface Magnetic Anisotropy change of 15 μ J / m 2 was induced by an electric field application of 400 mV/nm in the MTJ with a 0.5 nm thick FeCo layer. The realization of voltage-induced Anisotropy changes in an MTJ structure should have a large impact on the development of electric-field driven spintronic devices.
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Magnetic Anisotropy and strain states of 001 and 110 colossal magnetoresistance thin films
Applied Physics Letters, 2000Co-Authors: L M Berndt, Vincent Balbarin, Y. SuzukiAbstract:The Magnetic Anisotropy of epitaxial colossal magnetoresistance films on SrTiO3 substrates is dominated by the strain or magnetocrystalline Anisotropy depending on the orientation of the film. While the Magnetic Anisotropy of (001) films is determined by magnetocrystalline Anisotropy, that of (110) films is determined by magnetoelastic effects. Furthermore while the microstructure in the thin films has a significant effect on the coercive field, it has a correspondingly negligible effect on the Magnetic Anisotropy. We find a roughening surface morphology with increasing thickness that is more pronounced in (110) oriented films and can be attributed to the growth kinetics.
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the role of strain in Magnetic Anisotropy of manganite thin films
Applied Physics Letters, 1997Co-Authors: Y. Suzuki, Sang-wook Cheong, Harold Y Hwang, R B Van DoverAbstract:We show the importance of the role of strain in La0.7Sr0.3MnO3 films by revealing the dominance of stress Anisotropy effects over magnetocrystalline Anisotropy effects in the Magnetic Anisotropy of these films. Magnetic Anisotropy measurements of (001) and (110) La0.7Sr0.3MnO3 thin films on SrTiO3 and LaGaO3 substrates, with excellent structural quality, reveal twofold symmetry on (110) La0.7Sr0.3MnO3 films and fourfold symmetry on (001) films. Such symmetries can only be explained by stress Anisotropy contributions in the plane of the film. In conjunction with the thickness dependence of the Magnetic properties, the results indicate the dominant role of strain in the Magnetic properties of these doped manganites.
D. J. Freeland - One of the best experts on this subject based on the ideXlab platform.
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anisotropic lattice relaxation and uniaxial Magnetic Anisotropy in fe inas 100 4 2
Physical Review B, 2000Co-Authors: D. J. Freeland, M. Tselepi, J. A. C. BlandAbstract:The Magnetic Anisotropy and the lattice relaxation of epitaxial Fe films grown on InAs(100)-4×2 at room temperature have been studied using in situ magneto-optical Kerr effect and reflection high-energy electron diffraction. The experimental results demonstrate that the symmetry breaking associated with the intrinsic atomic scale structure of the reconstructed semiconductor surface induces an in-plane anisotropic lattice relaxation and an in-plane uniaxial Magnetic Anisotropy in the ultrathin region. We propose that this is a general phenomenon in ferroMagnetic/semiconductor heterostructures. © 2000 The American Physical Society.
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uniaxial Magnetic Anisotropy of epitaxial fe films on inas 100 4 2 and gaas 100 4 2
Journal of Applied Physics, 2000Co-Authors: D. J. Freeland, M. Tselepi, J. A. C. BlandAbstract:The evolution of the uniaxial Magnetic Anisotropy of ultrathin epitaxial Fe films grown on InAs(100)-4×2 and GaAs(100)-4×2 has been studied in situ by means of the magneto-optical Kerr effect. In Fe/InAs(100)-4×2, the uniaxial Magnetic Anisotropy easy axis direction along [011] was found to be rotated 90° compared with that of Fe/GaAs(100)-4×2 along [011]. Real-time reflection high energy electron diffraction measurements of Fe/InAs(100)-4×2 show that the lattice constant of the epitaxial Fe films relaxes remarkedly faster along the [011] direction than along the [011] direction in the same thickness range where the uniaxial Magnetic Anisotropy occurs. These results suggest that the symmetry-breaking atomic scale structure of the reconstructed semiconductor surface gives rise to the uniaxial Magnetic Anisotropy in a ferroMagnetic metal/semiconductor heterostructure via surface magneto-elastic interactions.
R A Buhrman - One of the best experts on this subject based on the ideXlab platform.
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thickness dependent magnetoelasticity and its effects on perpendicular Magnetic Anisotropy in ta cofeb mgo thin films
Physical Review B, 2016Co-Authors: P G Gowtham, Gregory M Stiehl, D C Ralph, R A BuhrmanAbstract:We report measurements of the in-plane magnetoelastic coupling in ultra-thin Ta|CoFeB|MgO layers as a function of uniaxial strain, conducted using a four-point bending apparatus. For annealed samples, we observe a strong dependence on the thickness of the CoFeB layer in the range 1.3-2.0 nm, which can be modeled as arising from a combination of effective surface and volume contributions to the magnetoelastic coupling. We point out that if similar thickness dependence exists for magnetoelastic coupling in response to biaxial strain, then the standard N\'eel model for the Magnetic Anisotropy energy acquires a term inversely proportional to the Magnetic layer thickness. This contribution can significantly change the overall Magnetic Anisotropy, and provides a natural explanation for the strongly nonlinear dependence of Magnetic Anisotropy energy on Magnetic layer thickness that is commonly observed for ultrathin annealed CoFeB|MgO films with perpendicular Magnetic Anisotropy.
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thickness dependent magnetoelasticity and its effects on perpendicular Magnetic Anisotropy in ta cofeb mgo thin films
Physical Review B, 2016Co-Authors: P G Gowtham, Gregory M Stiehl, D C Ralph, R A BuhrmanAbstract:We report measurements of the in-plane magnetoelastic coupling in both as-deposited and annealed ultrathin Ta/CoFeB/MgO layers as a function of uniaxial strain, conducted using a four-point bending apparatus. While as-deposited samples show only a weak dependence of the magnetoelastic coupling on the CoFeB layer thickness in the ultrathin regime $(l2\phantom{\rule{0.16em}{0ex}}\mathrm{nm})$, we observe the onset of a strong thickness dependence upon annealing. This dependence can be modeled as arising from a combination of effective surface and volume contributions to the magnetoelastic coupling. We point out that if similar thickness dependence exists for magnetoelastic coupling in response to biaxial strain, then the standard N\'eel model for the Magnetic Anisotropy energy acquires a term inversely proportional to the Magnetic layer thickness. This contribution can significantly change the overall Magnetic Anisotropy, and provides a natural explanation for the strongly nonlinear dependence of Magnetic Anisotropy energy on Magnetic layer thickness that is commonly observed for ultrathin annealed CoFeB/MgO films with perpendicular Magnetic Anisotropy.
Yutaka Ueda - One of the best experts on this subject based on the ideXlab platform.
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unusually large Magnetic Anisotropy in a cuo based semiconductor cu5v2o10
ChemInform, 2011Co-Authors: Chensheng Lin, Wendan Cheng, Atsushi Okazawa, Norimichi Kojima, Junichi Yamaura, Yutaka UedaAbstract:Magnetic measurements on single crystals of the title compound show that it exhibits an unexpected large Magnetic Anisotropy energy of up to 107 erg/cm3 at 5 K.
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unusually large Magnetic Anisotropy in a cuo based semiconductor cu5v2o10
Journal of the American Chemical Society, 2011Co-Authors: Chensheng Lin, Wendan Cheng, Atsushi Okazawa, Norimichi Kojima, Junichi Yamaura, Yutaka UedaAbstract:A CuO-based material Cu5V2O10 was successfully grown in a closed crucible using Sr(OH)2·8H2O as flux. The structure of Cu5V2O10 can be viewed as being composed of two types of zigzag Cu−O chains running along the b- and c-axes, which shows a two-dimensional crosslike framework with 12-column square tunnels along the a-axis. Magnetic measurements show that Cu5V2O10 exhibits unexpected large Magnetic Anisotropy, which is the first time Magnetic Anisotropy energy of ∼107 erg/cm3 in the CuO-based materials has been observed. The origins of large Anisotropy are suggested to arise from strong anisotropic exchanges due to the particular bonding geometry and the Jahn−Teller distortion of Cu2+ ions. Further, the band structure investigated by the GGA+U method suggests that Cu5V2O10 is a semiconductor.
