Connection between Structure and Electronic Properties in Epitaxial Magnetic Layers

1999 ◽  
Vol 570 ◽  
Author(s):  
K. N. Altmann ◽  
J. A. Con Foo ◽  
F. J. Himpsel ◽  
J. F. Kelly ◽  
M. G. Lagally ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Kerr Effect ◽  
Magnetic Coupling ◽  
Magnetic Multilayers ◽  
X Ray Scattering ◽  
Magnetic Layers ◽  
Wide Range ◽  
Spin Polarized ◽  
Quantum Well States

ABSTRACTThis study explores the consequences of structure on the electronic properties of magnetic multilayers. Epitaxial layers of Co and Cu are grown on Cu(100) in a new deposition system that couples sputter-deposition with MBE and contains a wide range of characterization tools, including RHEED, LEED, and Kerr effect. This system can be coupled in situ to spin-polarized, angle-resolved photoemission and to resonant, magnetic X-ray scattering, both employing synchrotron radiation. The interface structure turns out to be critical in determining the coercivity and the presence of quantum well states, which determine oscillatory magnetic coupling.

SHORT-PERIOD OSCILLATIONS OF THE MAGNETIC COUPLING OF EPITAXIAL GROWN Fe/Mo/Fe SANDWICHES ON Mo(100)

1992 ◽  
Vol 06 (14) ◽  
pp. 839-849 ◽  
Author(s):  
Z. Q. QIU ◽  
J. PEARSON ◽  
S. D. BADER
Keyword(s):  
Simple Model ◽  
Electron Diffraction ◽  
Hysteresis Loop ◽  
Kerr Effect ◽  
Exchange Coupling ◽  
Magnetic Coupling ◽  
Oscillatory Behavior ◽  
Ferromagnetic Coupling ◽  
Short Period

Epitaxial Fe / Mo / Fe sandwiches grown onto a Mo (100) single crystal were characterized in situ by electron diffraction and the magneto-optic Kerr effect. The intervening Mo layer is wedge shaped to facilitate the study of the magnetic coupling between the two (14-monolayer thick) Fe films as a function of Mo thickness. The exchange coupling between the Fe films across Mo was found to exhibit oscillatory behavior between antiferromagnetic (AF) and ferromagnetic coupling with a periodicity of ~3 ML of Mo . The shape of the hysteresis loop of the AF-coupled samples was calculated from a simple model that reproduces most of the experimental features.

Characterization and Modeling of Precipitation Kinetics in Aluminium 7000 Alloys

1999 ◽  
Vol 578 ◽  
Author(s):  
J.C. Werenskiold ◽  
A. Deschamps
Keyword(s):  
Internal State ◽  
Isothermal Heat Treatment ◽  
Precipitation Kinetics ◽  
Variable Model ◽  
Microstructural Parameters ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Wide Range ◽  
Modeling And Experiments

AbstractThe precipitation kinetics of 7108.70 aluminum alloy has been investigated in a wide range of temperatures by in situ Small Angle X-ray Scattering (SAXS) and Transmission Electron Microscopy (TEM), and computer modeled by use of an internal-state variable model which predicts the evolution of microstructural parameters. The modeling and experiments were done for isothermal heat treatment at 120, 140, 150, 160 and 170°C. The industrial T6 and T7 treatments have also been investigated.

Magneto-optical-Kerr-effect study of spin-polarized quantum-well states in a Au overlayer on a Co(0001) ultrathin film

1995 ◽  
Vol 51 (8) ◽  
pp. 5586-5589 ◽  
Author(s):  
R. Mégy ◽  
A. Bounouh ◽  
Y. Suzuki ◽  
P. Beauvillain ◽  
P. Bruno ◽  
...  
Keyword(s):  
Quantum Well ◽  
Kerr Effect ◽  
Effect Study ◽  
Ultrathin Film ◽  
Optical Kerr Effect ◽  
Spin Polarized ◽  
Magneto Optical Kerr Effect ◽  
Quantum Well States

Experimental setup forin situX-ray SAXS/WAXS/PDF studies of the formation and growth of nanoparticles in near- and supercritical fluids

2010 ◽  
Vol 43 (4) ◽  
pp. 729-736 ◽  
Author(s):  
Jacob Becker ◽  
Martin Bremholm ◽  
Christoffer Tyrsted ◽  
Brian Pauw ◽  
Kirsten Marie Ø. Jensen ◽  
...  
Keyword(s):  
Supercritical Fluids ◽  
Inorganic Nanoparticles ◽  
Great Promise ◽  
Synthesis Methods ◽  
Experimental Setup ◽  
X Ray ◽  
X Ray Scattering ◽  
Wide Range ◽  
Ray Scattering

The growing interest in inorganic nanoparticles for a wide range of applications is spurring a need for synthesis methods that allow a highly specific tailoring of material properties. Synthesis in supercritical fluids holds great promise for solving this problem, but so far the fundamental chemical processes taking place under these conditions are to a large extent unknown. Here the design, construction and application of a versatile experimental setup are reported; this setup enablesin situsynchrotron small-angle X-ray scattering/wide-angle X-ray scattering/pair distribution function (SAXS/WAXS/PDF) studies of the formation and growth of nanoparticles under supercritical fluid conditions.

Electronic States in Magnetic Quantum Wells

1993 ◽  
Vol 313 ◽  
Author(s):  
J. E. Ortega ◽  
F. J. Himpsel ◽  
G. J. Mankey ◽  
R. F. Willis
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Strong Evidence ◽  
Noble Metals ◽  
Electronic States ◽  
Magnetic Coupling ◽  
Spin Polarized ◽  
Quantum Well States

ABSTRACTWe have searched for the electronic states that mediate oscillatory magnetic coupling in superlattices, and have found strong evidence that these are quantum well states, which are created by quantizing the momentum of s,p-band states perpendicular to the interfaces. The quantum well picture also explains how quantum well states in noble metals become spin-polarized, due to a spin-dependent electron reflectivity at the interface with the ferromagnet. The resulting implications for magnetoresistance are discussed.

Quantum well States in Fe (100) Ultrathin Films Observed by Magneto-Optical Effect

1993 ◽  
Vol 313 ◽  
Author(s):  
Yoshishige Suzuki ◽  
Toshikazu Katayama
Keyword(s):  
Quantum Well ◽  
Ultrathin Films ◽  
Oscillation Period ◽  
Interlayer Thickness ◽  
Kerr Rotation ◽  
Magnetic Layers ◽  
Ultrathin Layers ◽  
Spin Polarized ◽  
Magneto Optical Effect ◽  
Quantum Well States

ABSTRACTWe report on the Magneto-optical Kerr rotation (<φ>K) spectra of ultrathin Fe films on Au or Ag (100) substrates and the φK oscillation due to interlayer thickness in Fe/Au/Fe sandwich films. In 3.5–4.5 eV, a new φK peak appears in the bcc-Fe (100) ultrathin films on the fcc-Au (100) surface and it shifts towards the higher energy side with increasing Fe layer thickness. The absolute value of eXy for 3Å (2ML) thick Fe layers is twice as large as that of bulk Fe at 3.7 eV. The thickness dependence of the transition energy of this new peak in the spectra is well explained by the concept of quantum well states in the Fe ultrathin layers, attributing the new transition to a transition from the majority spin Δ5 band ({px±i py), {dxz±i dyZ}; M=±l) to the Δ1 quantum well states (s, pz, dz2; M=0). The new peak is also observed in the Fe/Au (100) artificial superlattices. Using the εxy obtained experimentally for the Fe ultrathin films and the εxy of literature, we can reproduce the experimental φK spectra of the artificial superlattices by optical calculation. On the other hand, we cannot observe the same behavior for the ultrathin Fe films grown on a fcc-Ag (100) surface and covered by a Au (100) ultrathin film, although the εXy of Fe is different from that of the bulk and shows some structures in 2–3 eV. These structures around 2.5 eV are thought to be due to polarized Au atoms adjacent to an Fe layer.An oscillation of φK as a function of interlayer thickness, d, was observed in photon energy region between about 2.5 and 3.8 eV for the Fe (6Å) /Au (dÅ) /Fe (6A) sandwiched film. The oscillation period was about 10Å (5ML) of Au. The oscillation is thought to be closely related with a formation of spin polarized quantum well states of Δ1 band in Au layers sandwiched by magnetic layers.

QUANTUM WELL STATES IN METALLIC THIN LAYERS

1997 ◽  
Vol 04 (02) ◽  
pp. 361-370 ◽  
Author(s):  
J. E. ORTEGA ◽  
F. J. HIMPSEL ◽  
G. J. MANKEY ◽  
R. F. WILLIS
Keyword(s):  
Thin Film ◽  
Quantum Well ◽  
Magnetic Multilayers ◽  
Thin Layers ◽  
Bulk Solid ◽  
Quantum Well State ◽  
Spin Polarized ◽  
Photoemission Data ◽  
Oscillatory Coupling ◽  
Quantum Well States

When going from the bulk solid to a thin film of nanometer dimensions, the electronic structure becomes discretized in the perpendicular direction. These discrete states, also called thin film states and quantum well states, are clearly distinguished in photoemission experiments as two-dimensional and thickness-dependent modulations of the bulk spectra, although their observation is limited to highly perfect epitaxial systems. The photoemission data are well explained in the framework of a simple model for the electron wave function in a quantum well state. Thin film states become spin-polarized when growing on ferromagnetic substrates. Furthermore, spin-polarized, thickness-dependent modulations at a given energy lead to spin-dependent periodic oscillations of the density of states as a function of thickness, which are found to be responsible for the oscillatory coupling observed in magnetic multilayers.

scholarly journals MAGNETO-OPTIC CHARACTERIZATIONS OF SUPERLATTICES AND WEDGED SANDWICHES WITH OSCILLATORY INTERLAYER MAGNETIC COUPLING

1993 ◽  
Vol 07 (01n03) ◽  
pp. 414-418 ◽  
Author(s):  
S. D. BADER
Keyword(s):  
Kerr Effect ◽  
Magnetic Coupling ◽  
Long Period ◽  
Interlayer Magnetic Coupling ◽  
Magneto Optic

Three examples of magnetic coupling across metallic spacer layers are considered. Fe/Nb sputtered superlattices are observed to have as many as five antiferromagnetic oscillations, but a weak magnetoresistive anomaly. Epitaxial trilayers of Fe/Mo/Fe grown on Mo(100) and Co/Cu/Co grown on Cu(100) are observed to have short- and long-period oscillations, respectively. The trilayers are grown with wedged spacer layers and characterized in-situ by means of the magneto-optic Kerr effect.

scholarly journals Microstructural Evolution of Poly(ε-Caprolactone), Its Immiscible Blend, and In Situ Generated Nanocomposites

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2587
Author(s):  
Iurii Vozniak ◽  
Ramin Hosseinnezhad ◽  
Jerzy Morawiec ◽  
Andrzej Galeski
Keyword(s):  
Local Stress ◽  
Local Deformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Immiscible Polymers ◽  
X Ray Scattering ◽  
Wide Range ◽  
Immiscible Blend ◽  
Induced Crystallization

Polymer–polymer systems with special phase morphology were prepared, leading to an exceptional combination of strength, modulus, and ductility. Two immiscible polymers: poly(ε-caprolactone) (PCL) and polyhydroxyalkanoate (PHA) were used as components for manufacturing a nanoblend and a nanocomposite characterized by nanodroplet-matrix and nanofibril-matrix morphologies, respectively. Nanofibrils were formed by high shear of nanodroplets at sufficiently low temperature to stabilize their fibrillar shape by shear-induced crystallization. The effects of nanodroplet vs. nanofiber morphology on the tensile mechanical behavior of the nanocomposites were elucidated with the help of in situ 2D small-angle X-ray scattering, microcalorimetry and 2D wide-angle X-ray diffraction. For neat PCL and a PCL/PHA blend, the evolution of the structure under uniaxial tension was accompanied by extensive fragmentation of crystalline lamellae with the onset at strain e = 0.1. Limited lamellae fragmentation in the PCL/PHA composite occurred continuously over a wide range of deformations (e = 0.1–1.1) and facilitated plastic flow of the composite and was associated with the presence of a PHA nanofiber network that transferred local stress to the PCL lamellae, enforcing their local deformation. The PHA nanofibers acted as crystallization nuclei for PCL during their strain-induced melting–recrystallization.

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