Observations of Magnetic Domain Structure Change in Nd2Fe14B Magnets at Elevated Temperature with External Magnetic Field by Lorentz Microscopy

2015 ◽  
Vol 1754 ◽  
pp. 31-36 ◽  
Author(s):  
Toshimasa Suzuki ◽  
Koichi Kawahara ◽  
Haruka Tanaka ◽  
Kimihiro Ozaki
Keyword(s):  
Elevated Temperature ◽  
Domain Wall ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Magnetic Domain Wall ◽  
Lorentz Microscopy ◽  
Pinning Effect ◽  
In Situ Observations

ABSTRACTIn this study, we conducted the in-situ observations of the magnetic domain structure change in Nd2Fe14B magnets at elevated temperature by transmission electron microscopy (TEM) / Lorentz microscopy. The in-situ observations in Nd2Fe14B magnets revealed that the magnetization reversal easily occurred at the elevated temperature. At more than 180°C, the magnetic domain wall motion could be observed by applying the magnetic field of less than 20 mT. The motion of the magnetic domain wall was discontinuous and the domain wall jumped to one grain boundary to the neighboring grain boundary at 180°C. On the other hand, the continuous domain wall motion within grain interior as well as discontinuous domain wall motion was observed at 225°C, and some grain boundaries showed still strong pinning effect even at 225°C. The temperature dependence of the pinning effect of grain boundaries would not uniform.

Direct Observation of Reverse Magnetic Domain and Magnetic Domain Wall Motion in Nd-Fe-B Magnet at High Temperature by Lorentz Microscop

MRS Advances ◽  
2016 ◽  
Vol 1 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Toshimasa Suzuki ◽  
Koichi Kawahara ◽  
Masaya Suzuki ◽  
Kenta Takagi ◽  
Kimihiro Ozaki
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Domain Wall ◽  
Wall Motion ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Thin Foil ◽  
Magnetic Domain Wall

ABSTRACTWe conducted the in-situ observations of the magnetic domain structure change in Nd-Fe-B magnets at high temperature by transmission electron microscopy (TEM) / Lorentz microscopy with applying an external magnetic field. Prior to observation, a thin foil was magnetized by an external magnetic field of 2.0 T to almost saturation, then the magnetic domain structures were observed by the Fresnel mode with in-situ heating. At 225°C, reverse magnetic domains were found to generate in the thin foil sample without applying an external magnetic field. When we applied a magnetic field on the same direction to the pre-magnetization direction at 225°C, one magnetic domain wall was pinned by a grain boundary and the other magnetic domain wall moved. As the results, the reverse magnetic domain shrank then annihilated. When we cut the applied magnetic field, the reverse magnetic domain generated at almost the same location. On the other hand, when we applied a magnetic field to the foils in the opposite direction, the reverse domain started to grow, i.e., magnetic domain walls started to move. The observation results of the shrink or growth of the reverse domain showed that the pinning effect of grain boundary against domain wall motion would be different depending on the applied magnetic field direction. Moreover, domain walls was observed to be pinned by grain boundaries at elevated temperature, so that the coercivity of Nd-Fe-B magnet would occur by pinning mechanism.

Dependence of Magnetic Domain-Wall Motion on a Fast Changing Current

2009 ◽  
Vol 103 (19) ◽  
Author(s):  
Lars Bocklage ◽  
Benjamin Krüger ◽  
Toru Matsuyama ◽  
Markus Bolte ◽  
Ulrich Merkt ◽  
...  
Keyword(s):  
Domain Wall ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Magnetic Domain Wall

Distribution of critical current density for magnetic domain wall motion

2014 ◽  
Vol 115 (17) ◽  
pp. 17D508 ◽  
Author(s):  
S. Fukami ◽  
M. Yamanouchi ◽  
Y. Nakatani ◽  
K.-J. Kim ◽  
T. Koyama ◽  
...  
Keyword(s):  
Domain Wall ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Magnetic Domain Wall

scholarly journals Crossed-Ratchet Effects for Magnetic Domain Wall Motion

2008 ◽  
Vol 100 (3) ◽  
Author(s):  
A. Pérez-Junquera ◽  
V. I. Marconi ◽  
A. B. Kolton ◽  
L. M. Álvarez-Prado ◽  
Y. Souche ◽  
...  
Keyword(s):  
Domain Wall ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Magnetic Domain Wall ◽  
Ratchet Effects

Magnetic Domain Wall Motion

Spintronics ◽  
2021 ◽  
pp. 145-161
Author(s):  
Puja Dey ◽  
Jitendra Nath Roy
Keyword(s):  
Domain Wall ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Magnetic Domain Wall

Electric Field Driven Magnetic Domain Wall Motion in Iron Garnet Films

2009 ◽  
Vol 152-153 ◽  
pp. 143-146 ◽  
Author(s):  
A. Logginov ◽  
G. Meshkov ◽  
A. Nikolaev ◽  
E. Nikolaeva ◽  
A. Pyatakov ◽  
...  
Keyword(s):  
Domain Wall ◽  
Electric Field ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Gadolinium Gallium Garnet ◽  
Magnetic Domain Wall ◽  
Garnet Films ◽  
Dynamic Observation ◽  
Iron Garnet

The room temperature magnetoelectric effect was observed in epitaxial iron garnet films that appeared as magnetic domain wall motion induced by electric field. The films grown on gadolinium-gallium garnet substrates with various crystallographic orientations were examined. The effect was observed in (210) and (110) films and was not observed in (111) films. Dynamic observation of the domain wall motion in 800 kV/cm electric field pulses gave the domain wall velocity in the range 30÷50 m/s. Similar velocity was achieved in magnetic field pulse about 50 Oe.

Electrical endurance of Co/Ni wire for magnetic domain wall motion device

2013 ◽  
Vol 102 (22) ◽  
pp. 222410 ◽  
Author(s):  
S. Fukami ◽  
M. Yamanouchi ◽  
H. Honjo ◽  
K. Kinoshita ◽  
K. Tokutome ◽  
...  
Keyword(s):  
Domain Wall ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Magnetic Domain Wall
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