scholarly journals Artificial Magnetic Pattern Arrays Probed by Polarized Neutron Reflectivity

2020 ◽  
Author(s):  
Dmitry Gorkov ◽  
Boris P. Toperverg ◽  
Hartmut Zabel
Keyword(s):  
Thin Films ◽  
Neutron Scattering ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Magnetic Film ◽  
Magnetic Multilayers ◽  
Reduced Form ◽  
Neutron Reflectivity ◽  
Polarization Analysis ◽  
Polarized Neutron

Traditionally, neutron scattering is an essential method for the analysis of spin structures and spin excitations in bulk materials. Over the last 30 years, polarized neutron scattering in terms of reflectometry has also contributed largely to the analysis of magnetic thin films and magnetic multilayers. More recently it has been shown that polarized neutron reflectivity is, in addition, a suitable tool for the study of thin films laterally patterned with magnetic stripes or islands. We provide a brief overview of the fundamental properties of polarized neutron reflectivity, considering different domain states, domain fluctuations, and different domain sizes with respect to the neutron coherence volume. The discussion is exemplified by a set of simulated reflectivities assuming either complete polarization and polarization analysis, or a reduced form of polarized neutron reflectivity without polarization analysis. Furthermore, we emphasize the importance of the neutron coherence volume for the interpretation of specular and off-specular intensity maps, in particular when studying laterally non-homogeneous magnetic films. Finally, experimental results, fits, and simulations are shown for specular and off-specular scattering from a magnetic film that has been lithographically patterned into a periodic stripe array. These experiments demonstrate the different and mutually complementary information that can be gained when orienting the stripe array parallel or perpendicular to the scattering plane.

scholarly journals Artificial Magnetic Pattern Arrays Probed by Polarized Neutron Reflectivity

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 851
Author(s):  
Dmitry Gorkov ◽  
Boris P. Toperverg ◽  
Hartmut Zabel
Keyword(s):  
Thin Films ◽  
Neutron Scattering ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Magnetic Film ◽  
Magnetic Multilayers ◽  
Reduced Form ◽  
Neutron Reflectivity ◽  
Polarization Analysis ◽  
Polarized Neutron

Traditionally, neutron scattering is an essential method for the analysis of spin structures and spin excitations in bulk materials. Over the last 30 years, polarized neutron scattering in terms of reflectometry has also contributed largely to the analysis of magnetic thin films and magnetic multilayers. More recently it has been shown that polarized neutron reflectivity is, in addition, a suitable tool for the study of thin films laterally patterned with magnetic stripes or islands. We provide a brief overview of the fundamental properties of polarized neutron reflectivity, considering different domain states, domain fluctuations, and different domain sizes with respect to the neutron coherence volume. The discussion is exemplified by a set of simulated reflectivities assuming either complete polarization and polarization analysis, or a reduced form of polarized neutron reflectivity without polarization analysis. Furthermore, we emphasize the importance of the neutron coherence volume for the interpretation of specular and off-specular intensity maps, in particular when studying laterally non-homogeneous magnetic films. Finally, experimental results, fits, and simulations are shown for specular and off-specular scattering from a magnetic film that has been lithographically patterned into a periodic stripe array. These experiments demonstrate the different and mutually complementary information that can be gained when orienting the stripe array parallel or perpendicular to the scattering plane.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

Micromagnetic Simulations Of Domain Structures In Thin Films And Bulk Hard Magnets

1999 ◽  
Vol 5 (S2) ◽  
pp. 36-37
Author(s):  
Zhi-Xiong Cai ◽  
Yimei Zhu
Keyword(s):  
Thin Films ◽  
Magnetic Materials ◽  
Domain Structure ◽  
Easy Axis ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Electron Holography ◽  
Bulk Materials ◽  
Hard Magnetic Materials ◽  
Domain Structures

The shape anisotropy of a magnetic thin film competes with the easy-axis anisotropy, which gives rise to different domain structures compared to the bulk magnetic materials. Recent Lorentz microscope and electron holography and differential-phase-contrast experiments show complex domain structures with features not found in bulk materials seen by magneto-optic method.In this report we use micromagnetic simulation techniques to study the effect of thickness on the domain structure of magnetic thin films with various orientations relative to the easy axis and compare with those in the bulk materials. The results of the simulations can be used to compare with the data obtained using electron holography experiments to give us quantitative understanding of the domain structure in hard magnetic materials.We model the magnetic films with an array of dipoles of size 16×l6×Lz, where Lz the thickness of the sample.

Polarisation analysis of neutron reflectivity from magnetic thin films

1996 ◽  
Vol 4 (1) ◽  
pp. 251-260 ◽  
Author(s):  
C. Fermon ◽  
C. Miramond ◽  
F. Ott ◽  
G. Saux
Keyword(s):  
Thin Films ◽  
Magnetic Thin Films ◽  
Neutron Reflectivity ◽  
Polarisation Analysis

scholarly journals Tuning the properties of magnetic thin films by interaction with periodic nanostructures

2012 ◽  
Vol 3 ◽  
pp. 831-842 ◽  
Author(s):  
Ulf Wiedwald ◽  
Felix Haering ◽  
Stefan Nau ◽  
Carsten Schulze ◽  
Herbert Schletter ◽  
...  
Keyword(s):  
Self Assembly ◽  
Magnetic Domain ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Thermal Fluctuations ◽  
Magnetic Film ◽  
Switching Behavior ◽  
Defect Structures ◽  
Magnetization Direction ◽  
The Impact

The most important limitation for a significant increase of the areal storage density in magnetic recording is the superparamagnetic effect. Below a critical grain size of the used CoCrPt exchange-decoupled granular films the information cannot be stored for a reasonable time (typically ten years) due to thermal fluctuations arbitrary flipping of the magnetization direction. An alternative approach that may provide higher storage densities is the use of so-called percolated media, in which defect structures are imprinted in an exchange-coupled magnetic film. Such percolated magnetic films are investigated in the present work. We employ preparation routes that are based on (i) self-assembly of Au nanoparticles and (ii) homogeneous size-reduction of self-assembled polystyrene particles. On such non-close-packed nanostructures thin Fe films or Co/Pt multilayers are grown with in-plane and out-of-plane easy axis of magnetization. The impact of the particles on the magnetic switching behavior is measured by both integral magnetometry and magnetic microscopy techniques. We observe enhanced coercive fields while the switching field distribution is broadened compared to thin-film reference samples. It appears possible to tailor the magnetic domain sizes down to the width of an unperturbed domain wall in a continuous film, and moreover, we observe pinning and nucleation at or close to the imprinted defect structures.

Polarized neutron scattering from polycrystalline, exchange-biased magnetic multilayers

2005 ◽  
Vol 356 (1-4) ◽  
pp. 26-30 ◽  
Author(s):  
Amitesh Paul ◽  
Emmanuel Kentzinger ◽  
Ulrich Rücker ◽  
Daniel E. Bürgler ◽  
Peter Grünberg
Keyword(s):  
Neutron Scattering ◽  
Magnetic Multilayers ◽  
Polarized Neutron ◽  
Polarized Neutron Scattering

Micromagnetic Modeling: Theory and Applications in Magnetic Thin Films

MRS Bulletin ◽  
1995 ◽  
Vol 20 (10) ◽  
pp. 49-54 ◽  
Author(s):  
Jian-Gang Zhu
Keyword(s):  
Thin Films ◽  
Magnetic Hysteresis ◽  
Magnetic Domain ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Micromagnetic Modeling ◽  
Ferromagnetic System ◽  
Modeling Theory ◽  
Dynamic Description ◽  
Magnetization Processes

Micromagnetic theory concerns detailed magnetization configurations and the magnetization-reversal processes in a ferromagnetic system. By combining the original micromagnetic theory with a dynamic description of magnetization orientations, one can simulate complete magnetization processes and calculate important properties such as magnetic hysteresis and magnetic switching dynamics. Not only can micromagnetic simulation predict complex magnetic-domain configurations in a ferromagnetic system, it also can generate transient pictures showing how a complex domain configuration forms. Very important among these systems are ferromagnetic thin films, particularly those used in sensors and recording devices. Micromagnetic modeling not only has enriched our understanding of existing magnetic films but has also been used to successfully predict the magnetic properties of new film microstructures created for particular applications.In this article, a brief introduction of micromagnetic-modeling theory will be given. Modeling of soft and hard magnetic films will be discussed separately through two examples illustrating the essence of micromagnetic-magnetization processes in these films.

Neutron Scattering on Magnetic Thin Films

Neutron News ◽  
2011 ◽  
Vol 22 (4) ◽  
pp. 28-31 ◽  
Author(s):  
Frédéric Ott ◽  
Alexandre Bataille
Keyword(s):  
Thin Films ◽  
Neutron Scattering ◽  
Magnetic Thin Films
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