Magnetic Properties and Spin-Wave Excitations in Co/Mn Multilayers

SPIN ◽  
2020 ◽  
Vol 10 (01) ◽  
pp. 2050009
Author(s):  
A. Lekdadri ◽  
H. Salhi ◽  
H. Lassri ◽  
R. Moubah
Keyword(s):  
Magnetic Properties ◽  
Spin Wave ◽  
Spontaneous Magnetization ◽  
High Vacuum ◽  
Exchange Interactions ◽  
Interlayer Coupling ◽  
Ultra High Vacuum ◽  
Thermal Change ◽  
Cobalt Layer ◽  
Evaporation Technique

Co/Mn multilayers were prepared using evaporation technique under ultra-high vacuum conditions and their structural and magnetic properties were studied. The temperature dependence of the spontaneous magnetization [Formula: see text] was recorded for different cobalt layer thickness ([Formula: see text]) ranging from 19[Formula: see text]Å to 70[Formula: see text]Å. Bloch’s law describes satisfactory the thermal change of magnetization for all samples. In addition, the change of the spin-wave (SW) parameter [Formula: see text] versus [Formula: see text] was discussed. The torque magnetometry was utilized to extract the effective anisotropy ([Formula: see text]) and the interlayer coupling constant ([Formula: see text]) was determined from the in-plan M–H loops. An updated model based on SW theory was applied to describe the [Formula: see text] variation and to calculate the approximate values of exchange interactions for samples with different Co-layer thicknesses.

scholarly journals Effect of H Adsorption on the Magnetic Properties of an Fe Island on a W(110) Surface

2019 ◽  
Author(s):  
Marko Melander ◽  
Hannes Jonsson
Keyword(s):  
Magnetic Properties ◽  
Data Storage ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Low Dimensional ◽  
Low Dimensional Materials

<p>Low-dimensional materials, such as ultrathin films, nanoislands and wires, are actively being researched due to their interesting magnetic properties and possible technological applications for example in high density data storage. Results of calculations of an Fe nanoisland on a W(110) support are presented here with particular focus on the effect of hydrogen adsorption on its magnetic properties. This is an important consideration since hydrogen is present even under ultra-high vacuum conditions. The calculations are based on density functional theory within the generalized gradient approximation. The adsorption of H atoms is found to strongly decrease the magnetic moment of the Fe atoms they are bound to, down to less than a half in some cases as compared with the clean Fe island. The results show that it may be important to take the presence of hydrogen into account in measurements of magnetic properties of nanoislands.</p>

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.

Interrelation Between Structure and Magnetism of Ultra-Thin Mn Films Epitaxially Grown on (001) BCC Fe

1997 ◽  
Vol 475 ◽  
Author(s):  
S. Andrieu ◽  
Ph. Bauer ◽  
H. Fischer ◽  
M. Piecuch ◽  
M. Finazzi ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electron Diffraction ◽  
Structural Transition ◽  
Magnetic Circular Dichroism ◽  
Magnetic Transition ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
X Ray Absorption

ABSTRACTIn this paper, the interrelation between structural and magnetic properties of ultra-thin Mn films epitaxially grown on (001) bcc Fe is studied. The Mn growth and in-plane structure were controlled by electron diffraction (RHEED). The structures of the Mn films were determined by using X-Ray absorption spectroscopy (SEXAFS). Finally, the magnetic properties were studied by using X-Ray magnetic circular dichroïsm (XMCD). All the experiments were performed under ultra-high vacuum. As shown by XMCD experiments, a magnetic transition is observed at 2 Mn monolayers. The analysis of RHEED and SEXAFS experimental results clearly demonstrates that a structural transition comes with this magnetic transition.

scholarly journals Effect of H Adsorption on the Magnetic Properties of an Fe Island on a W(110) Surface

2019 ◽  
Author(s):  
Marko Melander ◽  
Hannes Jonsson
Keyword(s):  
Magnetic Properties ◽  
Data Storage ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Low Dimensional ◽  
Low Dimensional Materials

<p>Low-dimensional materials, such as ultrathin films, nanoislands and wires, are actively being researched due to their interesting magnetic properties and possible technological applications for example in high density data storage. Results of calculations of an Fe nanoisland on a W(110) support are presented here with particular focus on the effect of hydrogen adsorption on its magnetic properties. This is an important consideration since hydrogen is present even under ultra-high vacuum conditions. The calculations are based on density functional theory within the generalized gradient approximation. The adsorption of H atoms is found to strongly decrease the magnetic moment of the Fe atoms they are bound to, down to less than a half in some cases as compared with the clean Fe island. The results show that it may be important to take the presence of hydrogen into account in measurements of magnetic properties of nanoislands.</p>

Effects of ultra-high vacuum on crystallographic, recording and magnetic properties of thin film media

1998 ◽  
Vol 34 (4) ◽  
pp. 1576-1578 ◽  
Author(s):  
C. Gao ◽  
S. Wu ◽  
J.-P. Chen ◽  
R. Malmhall ◽  
C. Habermeier ◽  
...  
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
High Vacuum ◽  
Ultra High Vacuum

Structural and Magnetic Properties of Epitaxially Grown Fcc Fe/Cu(100) and Fe/CaF2/Si(111)

1994 ◽  
Vol 332 ◽  
Author(s):  
M.R. Scheinfein ◽  
S.D. Healy ◽  
K.R. Heim ◽  
Z.J. Yang ◽  
J.S. Drucker ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Kerr Effect ◽  
Room Temperature ◽  
High Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Ultra High Vacuum ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Imaging

ABSTRACTWe have used nanometer spatial resolution secondary electron and Auger electron imaging in an ultra-high vacuum scanning transmission electron microscope to characterize microstructure in ultrathin films of Fe/Cu(100) grown at room temperature and Fe/CaF2/Si(111) grown at room temperature and 150 C. Thin film microstructure was correlated in situ with magnetic properties by using the surface magneto-optic Kerr effect.

Thin Pyrolytic Graphite Films for Electron Microscope Substrates

1971 ◽  
Vol 29 ◽  
pp. 226-227 ◽  
Author(s):  
George H. N. Riddle ◽  
Benjamin M. Siegel
Keyword(s):  
Vacuum Chamber ◽  
Pyrolytic Graphite ◽  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Graphite Substrate ◽  
Nickel Substrate ◽  
Routine Procedure ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A routine procedure for growing very thin graphite substrate films has been developed. The films are grown pyrolytically in an ultra-high vacuum chamber by exposing (111) epitaxial nickel films to carbon monoxide gas. The nickel serves as a catalyst for the disproportionation of CO through the reaction 2C0 → C + CO2. The nickel catalyst is prepared by evaporation onto artificial mica at 400°C and annealing for 1/2 hour at 600°C in vacuum. Exposure of the annealed nickel to 1 torr CO for 3 hours at 500°C results in the growth of very thin continuous graphite films. The graphite is stripped from its nickel substrate in acid and mounted on holey formvar support films for use as specimen substrates.The graphite films, self-supporting over formvar holes up to five microns in diameter, have been studied by bright and dark field electron microscopy, by electron diffraction, and have been shadowed to reveal their topography and thickness. The films consist of individual crystallites typically a micron across with their basal planes parallel to the surface but oriented in different, apparently random directions about the normal to the basal plane.

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