scholarly journals In-situ Observations of Interaction of Magnetic Domain Wall with Grain Boundaries by Lorentz Microscopy

Materia Japan ◽  
2004 ◽  
Vol 43 (12) ◽  
pp. 1001-1001
Author(s):  
Sadahiro Tsurekawa ◽  
Tadao Watanabe ◽  
Yohei Ando ◽  
Koichi Kawahara
2015 ◽  
Vol 1754 ◽  
pp. 31-36 ◽  
Author(s):  
Toshimasa Suzuki ◽  
Koichi Kawahara ◽  
Haruka Tanaka ◽  
Kimihiro Ozaki

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.


2008 ◽  
Vol 62 (17-18) ◽  
pp. 2654-2656 ◽  
Author(s):  
H.H. Liu ◽  
X.K. Duan ◽  
R.C. Che ◽  
Z.F. Wang ◽  
X.F. Duan

SPIN ◽  
2016 ◽  
Vol 06 (01) ◽  
pp. 1650006 ◽  
Author(s):  
Bipul Das ◽  
Ting-Chieh Chen ◽  
Deng-Shiang Shiu ◽  
Lance Horng ◽  
Jong-Ching Wu

Here, we report an investigation of magnetic domain wall (DW) evolution and propagation in Y-shaped permalloy (Py) nanowire (NW) devices. The devices are fabricated using standard electron-beam lithography technique. Each device consists of three connected NWs that form a Y-junction structure with one branch connecting either symmetrically or asymmetrically to a circular disk for DW nucleation. The DW dynamics in the devices are studied by in situ magnetic force microscopy (MFM) by pinning the DWs to triangular notches at each branch of the two devices. We observe that the DW injection field values differ depending on whether they are connected to the circular disks symmetrically or asymmetrically. However, after they pass the Y-junctions, a selection is made by the DWs to propagate easily either through both or through only one particular outgoing branch of the devices. The experimental observations are analyzed by micromagnetic simulation. It can be inferred from the results that the influence of detailed geometrical shape of the devices leads to significantly different interactions among the innate topological defects and the notches with the injected DWs.


1999 ◽  
Vol 586 ◽  
Author(s):  
K. Kawahara ◽  
Y. Yagyu ◽  
S. Tsurekawa ◽  
T. Watanabe

ABSTRACTMagnetic domain structures in Fe-3wt%Si alloy have been observed by a Kerr microscopy to understand the interaction between the magnetic domain wall and grain boundaries. It was found that the domain structures in the vicinity of the grain boundary depend on the misorientation angle; the high angle random boundary disturbs the magnetic domain structure more than the low angle boundary. In addition to the misorientation angle, magnetic domain structures were affected by the inclination of the grain boundary plane. Moreover, dynamic observations of rearrangement of the magnetic domain structure during magnetization revealed that grain boundaries could act as the sink and/or the source for magnetic domains.


2011 ◽  
Vol 17 (S2) ◽  
pp. 1858-1859
Author(s):  
A Budruk ◽  
C Pathak ◽  
A Petford-Long ◽  
M De Graef

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.


1999 ◽  
Vol 85 (9) ◽  
pp. 6655-6659 ◽  
Author(s):  
R. H. Yu ◽  
S. Basu ◽  
Y. Zhang ◽  
A. Parvizi-Majidi ◽  
John Q. Xiao

Author(s):  
J.E. Wittig

Lorentz microscopy in the transmission electron microscope directly images magnetic domains. By changing the magnetic field of the electromagnetic lenses relative to the specimen plane, the movement of the magnetic domain walls and their interaction with microstructural features can be observed in situ. This type of experiment has successfully analyzed the microstructure-domain wall interactions in spinel ferrites and iron-rare-earth-boron magnetic materials. The domain wall motion reveals the qualitative pinning potential of grain boundaries, precipitates, inclusions, stacking faults, and cracks. In addition, these in situ experiments display the dynamics of magnetic domain nucleation. The current study investigates the magnetic domain wall movement in iron silicon alloys. Since magnetic properties such as intrinsic coercivity and permeability are structure sensitive, the influence of microstructure on domain wall movement dictates the soft magnetic behavior.Thin foils of iron-6.5 wt% silicon were prepared by electropolishing ribbons produced by melt spinning techniques. The magnetic domain walls were imaged in the defocused (Fresnel) mode with a Philips CM20T operated at 200 kV.


2013 ◽  
Vol 19 (S2) ◽  
pp. 790-791
Author(s):  
S. Hua ◽  
M. De Graef

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.


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