Magnetic domain pinning in patterned magneto-optical material

1999 ◽  
Vol 85 (8) ◽  
pp. 5980-5982 ◽  
Author(s):  
Te-Ho Wu ◽  
J. C. Wu ◽  
Y. W. Huang ◽  
Bing-Mau Chen ◽  
Han-Ping D. Schieh
2008 ◽  
Vol 78 (7) ◽  
Author(s):  
Jungtaek Kim ◽  
D. Y. Shin ◽  
Sanghoon Lee ◽  
X. Liu ◽  
J. K. Furdyna

2008 ◽  
Vol 103 (7) ◽  
pp. 07D118 ◽  
Author(s):  
Sun-Young Yea ◽  
Sun-Jae Chung ◽  
Hyunji Son ◽  
Sanghoon Lee ◽  
X. Liu ◽  
...  

2006 ◽  
Vol 100 (3) ◽  
pp. 033904 ◽  
Author(s):  
Stan Konings ◽  
Jorge Miguel ◽  
Jeroen Goedkoop ◽  
Julio Camarero ◽  
Jan Vogel

1999 ◽  
Vol 38 (Part 1, No. 3B) ◽  
pp. 1832-1834 ◽  
Author(s):  
Jong-Ching Wu ◽  
Ying-Wen Huang ◽  
Bing-Mau Chen ◽  
Te-ho Wu ◽  
Han-PingD. Shieh

1998 ◽  
Vol 22 (S_2_MORIS_97) ◽  
pp. S2_145-148 ◽  
Author(s):  
Te-ho Wu ◽  
J.C. Wu ◽  
Bing-Mau Chen ◽  
Han-Ping D. Shieh

Author(s):  
J.N. Chapman ◽  
P.E. Batson ◽  
E.M. Waddell ◽  
R.P. Ferrier

By far the most commonly used mode of Lorentz microscopy in the examination of ferromagnetic thin films is the Fresnel or defocus mode. Use of this mode in the conventional transmission electron microscope (CTEM) is straightforward and immediately reveals the existence of all domain walls present. However, if such quantitative information as the domain wall profile is required, the technique suffers from several disadvantages. These include the inability to directly observe fine image detail on the viewing screen because of the stringent illumination coherence requirements, the difficulty of accurately translating part of a photographic plate into quantitative electron intensity data, and, perhaps most severe, the difficulty of interpreting this data. One solution to the first-named problem is to use a CTEM equipped with a field emission gun (FEG) (Inoue, Harada and Yamamoto 1977) whilst a second is to use the equivalent mode of image formation in a scanning transmission electron microscope (STEM) (Chapman, Batson, Waddell, Ferrier and Craven 1977), a technique which largely overcomes the second-named problem as well.


Author(s):  
Yalcin Belli

Fe-Cr-Co alloys have great technological potential to replace Alnico alloys as hard magnets. The relationship between the microstructures and the magnetic properties has been recently established for some of these alloys. The magnetic hardening has been attributed to the decomposition of the high temperature stable phase (α) into an elongated Fe-rich ferromagnetic phase (α1) and a weakly magnetic or non-magnetic Cr-rich phase (α2). The relationships between magnetic domains and domain walls and these different phases are yet to be understood. The TEM has been used to ascertain the mechanism of magnetic hardening for the first time in these alloys. The present paper describes the magnetic domain structure and the magnetization reversal processes in some of these multiphase materials. Microstructures to change properties resulting from, (i) isothermal aging, (ii) thermomagnetic treatment (TMT) and (iii) TMT + stepaging have been chosen for this investigation. The Jem-7A and Philips EM-301 transmission electron microscopes operating at 100 kV have been used for the Lorentz microscopy study of the magnetic domains and their interactions with the finely dispersed precipitate phases.


Author(s):  
K. Shi rota ◽  
A. Yonezawa ◽  
K. Shibatomi ◽  
T. Yanaka

As is well known, it is not so easy to operate a conventional transmission electron microscope for observation of magnetic materials. The reason is that the instrument requires re-alignment of the axis and re-correction of astigmatism after each specimen shift, as the lens field is greatly disturbed by the specimen. With a conventional electron microscope, furthermore, it is impossible to observe magnetic domains, because the specimen is magnetized to single orientation by the lens field. The above mentioned facts are due to the specimen usually being in the lens field. Thus, special techniques or systems are usually required for magnetic material observation (especially magnetic domain observation), for example, the technique to switch off the objective lens current and Lorentz microscopy. But these cannot give high image quality and wide magnification range, and furthermore Lorentz microscopy is very complicated.


Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.


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