In situ investigation of the magnetic domain wall in Permalloy thin film by Lorentz electron microscopy

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.

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Differential Domain Wall Propagation in Y-Shaped Permalloy Nanowire Devices

SPIN ◽

10.1142/s2010324716500065 ◽

2016 ◽

Vol 06 (01) ◽

pp. 1650006 ◽

Cited By ~ 2

Author(s):

Bipul Das ◽

Ting-Chieh Chen ◽

Deng-Shiang Shiu ◽

Lance Horng ◽

Jong-Ching Wu

Keyword(s):

Domain Wall ◽

Magnetic Force ◽

Magnetic Domain ◽

Topological Defects ◽

Circular Disk ◽

Geometrical Shape ◽

Magnetic Domain Wall ◽

Force Microscopy ◽

Junction Structure

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.

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Reversible magnetic domain-wall motion under an electric field in a magnetoelectric thin film

Applied Physics Letters ◽

10.1063/1.2900886 ◽

2008 ◽

Vol 92 (11) ◽

pp. 112509 ◽

Cited By ~ 79

Author(s):

Tien-Kan Chung ◽

Gregory P. Carman ◽

Kotekar P. Mohanchandra

Keyword(s):

Thin Film ◽

Domain Wall ◽

Electric Field ◽

Wall Motion ◽

Magnetic Domain ◽

Domain Wall Motion ◽

Magnetic Domain Wall

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Magnetic domain wall contrast under zero domain contrast conditions in spin polarized low energy electron microscopy

Ultramicroscopy ◽

10.1016/j.ultramic.2019.02.026 ◽

2019 ◽

Vol 200 ◽

pp. 132-138 ◽

Cited By ~ 3

Author(s):

Chao Zhou ◽

Gong Chen ◽

Jia Xu ◽

Jianhui Liang ◽

Kai Liu ◽

...

Keyword(s):

Electron Microscopy ◽

Domain Wall ◽

Magnetic Domain ◽

Low Energy ◽

Energy Electron ◽

Magnetic Domain Wall ◽

Spin Polarized ◽

Low Energy Electron

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In-situ Lorentz TEM Study of Magnetic Domain Wall Mobility in Amartensitic Ni-Mn-Ga Alloy

Microscopy and Microanalysis ◽

10.1017/s1431927611010166 ◽

2011 ◽

Vol 17 (S2) ◽

pp. 1858-1859

Author(s):

A Budruk ◽

C Pathak ◽

A Petford-Long ◽

M De Graef

Keyword(s):

Domain Wall ◽

Magnetic Domain ◽

Magnetic Domain Wall ◽

Domain Wall Mobility ◽

Wall Mobility

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

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

Materia Japan ◽

10.2320/materia.43.1001 ◽

2004 ◽

Vol 43 (12) ◽

pp. 1001-1001

Author(s):

Sadahiro Tsurekawa ◽

Tadao Watanabe ◽

Yohei Ando ◽

Koichi Kawahara

Keyword(s):

Domain Wall ◽

Grain Boundaries ◽

Magnetic Domain ◽

Magnetic Domain Wall ◽

Lorentz Microscopy

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Magnetic domain wall movement in iron silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100151052 ◽

1993 ◽

Vol 51 ◽

pp. 1044-1045

Author(s):

J.E. Wittig

Keyword(s):

Domain Wall ◽

Domain Walls ◽

Magnetic Domain ◽

Magnetic Domain Wall ◽

Silicon Alloys ◽

Iron Silicon ◽

Domain Wall Movement ◽

Wall Movement ◽

Magnetic Domain Walls

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.

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