Anisotropy Energies and Critical Behavior of Ultrathin Ni(111) Films Grown on Smooth and Rough W(110) (invited)

1991 ◽  
Vol 231 ◽  
Author(s):  
Yi Li ◽  
K. Baberschke
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Film Thickness ◽  
Critical Exponent ◽  
Critical Behavior ◽  
Induced Anisotropy ◽  
Effective Anisotropy ◽  
Stress Induced Anisotropy ◽  
Surface Crystal

Abstract6 to 80 Å thin Ni(111) films were prepared on smooth and rough W(110) substrates in UHV and characterized by LEED and Auger spectroscopies. The measurements of the magnetic properties were carried out in situ by ferromagnetic resonance at 9 GHz between 300 and 600 K. We found that the effective anisotropies, which consist of surface, crystal, and stress induced anisotropy, increase with decreasing film thickness and temperature. The roughness of the substrate results in the drastic decrease of the effective anisotropy. This is attributed to the change of the surface structure and the stress within the Ni films. Furthermore we found that the Curie temperature Tc and the critical exponent β of Ni films on the smooth and rough substrates show no change.

A Comparison of Magnetic Properties of Thin Films of Fe/GaAs(100) and Ni/MICA

1992 ◽  
Vol 280 ◽  
Author(s):  
Bruce Andrien ◽  
David Miller
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Film Thickness ◽  
Gaas Substrate ◽  
High Vacuum ◽  
Auger Spectroscopy ◽  
Ultra High Vacuum ◽  
In Situ Adsorption

ABSTRACTA comparison between the morphology and magnetic properties has been made with thin films of Fe grown on GaAs(lOO) and of Ni grown on natural mica in the 10Å to 1000Å thickness range, in ultra high vacuum. The films are characterized in-situ by Auger spectroscopy and by an in-situ UHV M/H hysteresis loop tracer. If the films are thermally annealed, above 550°C for less than a few seconds, the film morphology changes. The Fe films form surface assembled clusters which are epitaxial with the GaAs substrate with diameters of order of the original average film thickness, while the Ni films grow large grains. The Auger signals show that the Fe clustering exposes the GaAs substrate while the Ni films are continuous and cover the mica substrate. In-situ adsorption studies of CO on the Ni films were consistent with the continuous nature of the Ni films. Hysteresis M/H curves are taken as a function of thickness and plots of coercivity versus film thickness or average cluster size shows a maximum near 100Å for both the Ni and the Fe films. The maximum is believed to be due to a trade-off between super-paramagnetism and magnetostatic forces, but with the grains in the Ni film playing the role of the clusters in the Fe film.

scholarly journals Film thickness dependence of microstructures and magnetic properties in single-layered FePt films by in-situ annealing

2011 ◽  
Vol 519 (20) ◽  
pp. 6964-6968 ◽  
Author(s):  
S.C. Chen ◽  
T.H. Sun ◽  
C.L. Chang ◽  
C.L. Shen ◽  
P.C. Kuo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Film Thickness ◽  
Thickness Dependence

MAGNETIC PROPERTIES OF NANOCRYSTALLINE CO-FERRITE FILMS DEPOSITED ON SINGLE-CRYSTAL SiO2 SUBSTRATES USING PULSED LASER DEPOSITION

2008 ◽  
Vol 15 (01n02) ◽  
pp. 71-75 ◽  
Author(s):  
J. H. YIN ◽  
J. DING ◽  
B. H. LIU ◽  
X. S. MIAO ◽  
J. B. YI ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Film Thickness ◽  
Magnetic Anisotropy ◽  
Residual Strain ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Post Annealing ◽  
In Situ Heating ◽  
Ferrite Films

Co-ferrite films were prepared using pulsed laser deposition with both post-annealing and in situ heating processes. Magnetic properties of these films were studied in the function of temperature, film thickness, and substrate. The films using post-annealing processes exhibited isotropic microstructure, and the coercivity showed no obvious magnetic anisotropy and no strong dependence on film thickness. Co-ferrite films using in situ heating exhibited (111) highly textured structure and possessed perpendicular anisotropy as well as large coercivity. The preferential texture and magnetic anisotropy were closely associated with substrate temperature and thickness. Perpendicular Hc over 12.5 kOe was obtained in the 33 nm Co-ferrite film deposited on single crystal quartz substrate at 550°C. The high coercivity and perpendicular coercivity may be attributed to the nanocrystalline grain, textured orientation, and large residual strain in these films since large residual strain may induce strong stress anisotropy.

scholarly journals Magnetic Properties and Growth‐Induced Anisotropy in Yttrium Thulium Iron Garnet Thin Films

2021 ◽  
pp. 2100452
Author(s):  
Ethan R. Rosenberg ◽  
Kai Litzius ◽  
Justin M. Shaw ◽  
Grant A. Riley ◽  
Geoffrey S. D. Beach ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Induced Anisotropy ◽  
Iron Garnet

scholarly journals Precise control of Jeff=12 magnetic properties in Sr2IrO4 epitaxial thin films by variation of strain and thin film thickness

2020 ◽  
Vol 102 (21) ◽  
Author(s):  
Stephan Geprägs ◽  
Björn Erik Skovdal ◽  
Monika Scheufele ◽  
Matthias Opel ◽  
Didier Wermeille ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Film Thickness ◽  
Epitaxial Thin Films ◽  
Thin Film Thickness ◽  
Precise Control

scholarly journals A hyperelastic model for soils with stress-induced and inherent anisotropy

2021 ◽  
Author(s):  
Marcin Cudny ◽  
Katarzyna Staszewska
Keyword(s):  
Small Strain ◽  
Induced Anisotropy ◽  
Dynamic Simulations ◽  
Inherent Anisotropy ◽  
Directional Model ◽  
Model Response ◽  
Hyperelastic Model ◽  
Stress Induced Anisotropy ◽  
Stress Invariant ◽  
Independent Model

AbstractIn this paper, modelling of the superposition of stress-induced and inherent anisotropy of soil small strain stiffness is presented in the framework of hyperelasticity. A simple hyperelastic model, capable of reproducing variable stress-induced anisotropy of stiffness, is extended by replacement of the stress invariant with mixed stress–microstructure invariant to introduce constant inherent cross-anisotropic component. A convenient feature of the new model is low number of material constants directly related to the parameters commonly used in the literature. The proposed description can be incorporated as a small strain elastic core in the development of some more sophisticated hyperelastic-plastic models of overconsolidated soils. It can also be used as an independent model in analyses involving small strain problems, such as dynamic simulations of the elastic wave propagation. Various options and features of the proposed anisotropic hyperelastic model are investigated. The directional model response is compared with experimental data available in the literature.

In Situ Diagnostics of Vuv Laser Cvd of Semiconductor Interfaces by Ftir Spectroscopy and Spectroscopic Ellipsometry

1995 ◽  
Vol 397 ◽  
Author(s):  
M. Barth ◽  
J. Knobloch ◽  
P. Hess
Keyword(s):  
Film Thickness ◽  
Bulk Material ◽  
Substrate Surface ◽  
Cluster Formation ◽  
Interface Layer ◽  
Native Oxide ◽  
Initial Growth ◽  
Difference Spectra ◽  
Si Substrates

ABSTRACTThe growth of high quality amorphous hydrogenated semiconductor films was explored with different in situ spectroscopic methods. Nucleation of ArF laser-induced CVD of a-Ge:H on different substrates was investigated by real time ellipsometry, whereas the F2 laser (157nm) deposition of a-Si:H was monitored by FTIR transmission spectroscopy. The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage, which in fact determines the electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at a thickness of 16 Å for atomically smooth hydrogen-terminated c-Si substrates, whereas on native oxide covered c-Si substrates the bulk volume void fractions are not reached until 35 Å film thickness. For the first time we present a series of IR transmission spectra with monolayer resolution of the initial growth of a-Si:H. Hereby the film thickness was measured simultaneously using a quartz crystal microbalance with corresponding sensitivity. The results give evidence for cluster formation with a coalescence radius of about 20 Å. Difference spectra calculated for layers at different depths with definite thickness reveal that the hydrogen-rich interface layer stays at the substrate surface and does not move with the surface of the growing film. The decrease of the Urbach energy switching from native oxide to H-terminated substrates suggests a strong influence of the interface morphology on the bulk material quality.

Sign in / Sign up

Export Citation Format

Share Document