Spin Polarized Electron Spectroscopies of 3d and 4f Systems

1993 ◽  
Vol 313 ◽  
Author(s):  
H. Hopster
Keyword(s):  
Transition Metals ◽  
Magnetic Coupling ◽  
Atomic Layer ◽  
Antiferromagnetic Order ◽  
Layer By Layer ◽  
Temperature Dependent ◽  
Spin Polarized ◽  
Surface Magnetization ◽  
Surface Spin ◽  
Electron Energy Loss

AbstractRecent results from spin polarized electron spectroscopie studies of surfaces and ultrathin films are presented. The Magnetic coupling of 3d transition Metals (Cr,Mn) to the Fe (100) surface is studied by spin polarized electron energy loss spectroscopy. The first atomic layer of Cr and mn aligns antiparallel to the Fe. For larger thicknesses we find evidence for layer-by-layer antiferromagnetic order. In the range of 1–6 atomic layers the behavior is more complex with the surface of the Cr films showing preferential ferromagnetic alignment while the mn surface aligns antiparallel to the Fe substrate.Secondary electrons from Gd (0001) surfaces are shown to be highly spin polarized. However, no enhancement mechanism at low kinetic energy as in the 3d transition metals is observed indicating the absence of strongly spin dependent inelastic scattering in Gd. Temperature dependent spin polarized 4f photoemis-sion results show almost complete polarization demonstrating ferromagnetic surface coupling. However, a perpendicular surface magnetization component is found indicating surface spin canting. A large enhancement of the surface Curie temperature is also present.

SPIN-POLARIZED ELECTRON ENERGY LOSS SPECTROSCOPY

1994 ◽  
Vol 01 (01) ◽  
pp. 89-96 ◽  
Author(s):  
H. HOPSTER
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Magnetic Moments ◽  
Antiferromagnetic Order ◽  
Layer By Layer ◽  
Spin Polarized ◽  
Surface Magnetization ◽  
Electron Hole Pair ◽  
Electron Energy Loss

Spin-polarized electron energy loss spectroscopy (SPEELS) probes the spin-dependent electron-hole pair excitation spectrum at surfaces. It is a very surface sensitive method for the detection of surface magnetization. Indirectly, information on surface magnetic moments is obtained. SPEELS is capable of resolving layer-by-layer antiferromagnetic order as found in 3d metal (Cr, Mn, V) films on Fe(100).

scholarly journals Spin Polarized Photoemission Studies of Surfaces and Thin Films

1991 ◽  
Vol 231 ◽  
Author(s):  
Peter D. Johnson ◽  
N.B. Brookes ◽  
Y. Chang
Keyword(s):  
Binding Energy ◽  
First Principles ◽  
Magnetic Coupling ◽  
Interface State ◽  
First Principles Calculation ◽  
Layer By Layer ◽  
Minority Spin ◽  
Interfacial Electronic Structure ◽  
Spin Polarized ◽  
Magnetic States

AbstractSpin polarized photoemission is used to study the magnetic states associated with the clean iron (001) surface. These studies reveal evidence for a minority spin surface state in agreement with a first principles calculation. Studies of the same surface with silver and chromium epitaxial overlayers reveal evidence for interface states derived from this state found on the clean surface. In the case of the silver overlayer the binding energy of the new state is found to be dependent on the layer by layer thickness of the overlayer. With chromium overlayers the binding energy for the same interface state does not show the same thickness dependence. However a second interface state is observed immediately below the Fermi level. These changes in the interfacial electronic structure have implications for any modelling of magnetic coupling in multilayers dependent on the magnetic properties of the interface.

In Situ Analysis of Surface Contaminant Desorption during Low-Temperature Silicon Substrate Cleaning using Reflection Electron Energy Loss Spectrometry

1992 ◽  
Vol 259 ◽  
Author(s):  
Selmer S. Wong ◽  
Shouleh Nikzad ◽  
Channing C. Ahn ◽  
Aimee L. Smith ◽  
Harry A. Atwater
Keyword(s):  
Low Temperature ◽  
Energy Loss ◽  
Electron Energy ◽  
Core Loss ◽  
Temperature Dependent ◽  
Electron Energy Loss Spectrometry ◽  
Analysis Technique ◽  
Chemical Analysis Technique ◽  
Electron Energy Loss

ABSTRACTWe have employed reflection electron energy loss spectrometry (REELS), a surface chemical analysis technique, in order to analyze contaminant coverages at the submonolayer level during low-temperature in situ cleaning of hydrogen-terminated Si(100). The chemical composition of the surface was analyzed by measurements of the C K, O K and Si L2,3 core loss intensities at various stages of the cleaning. These results were quantified using SiC(100) and SiO2 as reference standards for C and O coverage. Room temperature REELS core loss intensity analysis after sample insertion reveals carbon at fractional monolayer coverage. We have established the REELS detection limit for carbon coverage to be 5±2% of a monolayer. A study of temperature-dependent hydrocarbon desorption from hydrogen-terminated Si(100) reveals the absence of carbon on the surface at temperatures greater than 200°C. This indicates the feasibility of epitaxial growth following an in situ low-temperature cleaning and also indicates the power of REELS as an in situ technique for assessment of surface cleanliness.

Rheed Studies of a-Axis Oriented DyBa2Cu3O7 Films Grown by All-MBE

1997 ◽  
Vol 502 ◽  
Author(s):  
Ivan Bozovic ◽  
J. N. Eckstein ◽  
Natasha Bozovic ◽  
J. O'Donnell
Keyword(s):  
Phase Transitions ◽  
Secondary Phase ◽  
Atomic Layer ◽  
High Energy ◽  
Layer By Layer ◽  
Growth Modes ◽  
Flow Surface ◽  
Surface Phase Transitions

ABSTRACTReal-time, in-situ surface monitoring by reflection high-energy electron diffraction (RHEED) has been the key enabling component of atomic-layer-by-layer molecular beam epitaxy (ALL-MBE) of complex oxides. RHEED patterns contain information on crystallographic arrangements and long range order on the surface; this can be made quantitative with help of numerical simulations. The dynamics of RHEED patterns and intensities reveal a variety of phenomena such as nucleation and dissolution of secondary-phase precipitates, switching between growth modes (layer-by-layer, step-flow), surface phase transitions (surface reconstruction, roughening, and even phase transitions induced by the electron beam itself), etc. Some of these phenomena are illustrated here, using as a case study our recent growth of atomically smooth a-axis oriented DyBa2Cu3O7 films.

Spin-Polarized Splittings in the Temperature-Dependent Reflectance of EuO

1969 ◽  
Vol 22 (25) ◽  
pp. 1385-1388 ◽  
Author(s):  
J. Feinleib ◽  
W. J. Scouler ◽  
J. O. Dimmock ◽  
J. Hanus ◽  
T. B. Reed ◽  
...  
Keyword(s):  
Temperature Dependent ◽  
Spin Polarized

scholarly journals Crystal Structure Dependence of Antiferromagnetic Coupling in FE/SI Multilayers

1995 ◽  
Vol 384 ◽  
Author(s):  
R. P. Michel ◽  
A. Chaiken ◽  
M. A. Wall
Keyword(s):  
Crystal Structure ◽  
Magnetic Coupling ◽  
Antiferromagnetic Coupling ◽  
Temperature Dependent ◽  
Layered Systems ◽  
Metal Insulator ◽  
Structure Dependence ◽  
Metallic Conductor ◽  
Metal Metal ◽  
Cscl Structure

ABSTRACTRecent reports of temperature dependent antiferromagnetic coupling in Fe/Si multilayers have motivated the generalization of models describing magnetic coupling in metal/metal multilayers to metal/insulator and metal/semiconductor layered systems. Interesting dependence of the magnetic properties on layer thickness and temperature are predicted. We report measurements that show the antiferromagnetic (AF) coupling observed in Fe/Si multilayers is strongly dependent on the crystalline coherence of the silicide interlayer. Electron diffraction images show the silicide interlayer has a CsCl structure. It is not clear at this time whether the interlayer is a poor metallic conductor or a semiconductor so the relevance of generalized coupling theories is unclear.

Layer-by-Layer Molecular Assemblies for Dye-Sensitized Photoelectrosynthesis Cells Prepared by Atomic Layer Deposition

2017 ◽  
Vol 139 (41) ◽  
pp. 14518-14525 ◽  
Author(s):  
Degao Wang ◽  
Matthew V. Sheridan ◽  
Bing Shan ◽  
Byron H. Farnum ◽  
Seth L. Marquard ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Layer By Layer ◽  
Molecular Assemblies ◽  
Dye Sensitized ◽  
Layer Deposition
Sign in / Sign up

Export Citation Format

Share Document