Magnetization reconstruction from differential phase contrast Lorentz microscopy and magnetic force microscopy

1998 ◽  
Vol 34 (4) ◽  
pp. 2324-2333 ◽  
Author(s):  
M. Wdowin ◽  
J.J. Miles ◽  
B.K. Middleton ◽  
M. Aziz
Keyword(s):  
Phase Contrast ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Lorentz Microscopy ◽  
Force Microscopy ◽  
Differential Phase ◽  
Differential Phase Contrast

User Access to Lorentz Microscopy at the NCEM, LBNL, Berkeley.

1998 ◽  
Vol 4 (S2) ◽  
pp. 472-473
Author(s):  
K. Verbist ◽  
C. Nelson ◽  
K. Krishnan
Keyword(s):  
Electron Microscope ◽  
Phase Contrast ◽  
Limited Range ◽  
Objective Lens ◽  
Image Filter ◽  
Lorentz Microscopy ◽  
Differential Phase ◽  
Free Sample ◽  
User Access ◽  
Differential Phase Contrast

A standard Philips CM200FEG electron microscope, without the special Lorentz lens, has been optimized for Lorentz imaging. The necessary field-free sample region is obtained by switching off the objective lens in the free lens mode. The limited range of magnification is compensated for by a post-column Gatan image filter (GIF) which magnifies by a factor of _ 20. Fresnel imaging is performed by defocusing with the diffraction lens. The use of low angle diffraction, in combination with the apertures located at the selected area aperture plane, allow Foucault imaging. The TEM analog of differential phase contrast (DPC) imaging has been implemented. This method makes it possible to obtain quantitave induction maps of the in-plane magnetization. TEM DPC is based on a series of Foucault images, recorded with different incremental beam tilts, which are processed to yield images equivalent to the quadrant signals obtained by the STEM DPC technique.

Differential phase contrast Lorentz microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 758-759
Author(s):  
Ian R. McFadyen
Keyword(s):  
Electron Beam ◽  
Phase Shift ◽  
Magnetic Induction ◽  
Phase Contrast ◽  
Magnetic Films ◽  
Electron Wave ◽  
Lorentz Microscopy ◽  
Differential Phase ◽  
Phase Derivative ◽  
Differential Phase Contrast

Transmission electron microscopy can provide high spatial resolution information on domain structures in thin magnetic films provided the interaction between the electron beam and the magnetic sample is correctly utilised: As an electron beam passes through a magnetic sample it suffers a phase shift due to the magnetic induction of the sample and the associated stray fields. The derivative of this phase shift is a direct measure of the in-plane magnetic induction integrated along the electron trajectory, Therefore measurement of this phase derivative would provide the integrated in-plane induction directly. The conventional phase contrast techniques of Fresnel and Foucault Lorentz microscopy provide image contrast which has a very non-linear relationship to the above mentioned phase derivative. Differential phase contrast Lorentz microscopy (DPC), on the other hand, does provide direct, high resolution information on the phase derivative of the electron wave as it leaves tile sample. In this technique a focused probe of electrons is scanned cross the sample and a position sensitive detector in the far field measures two orthogonal components of the probe deflection angle at each point in the scan. This corresponds to the derivative of the phase of the electron wave as it leaves the sample, and thus to the integral of the in-plane induction at each point.

scholarly journals Comparison of Magnetic Domain Wall Images using Lorentz Microscopy and Magnetic Force Microscopy

2013 ◽  
Vol 19 (S2) ◽  
pp. 790-791
Author(s):  
S. Hua ◽  
M. De Graef
Keyword(s):  
Domain Wall ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Magnetic Domain ◽  
Magnetic Domain Wall ◽  
Lorentz Microscopy ◽  
Force Microscopy

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

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

Study of MFM Application in Semiconductor Failure Analysis

2004 ◽  
Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao
Keyword(s):  
Magnetic Field ◽  
Failure Analysis ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Current Flow ◽  
Force Microscopy ◽  
The Magnetic Field ◽  
A Current

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.

scholarly journals Magnetic Force Microscopy: Comparison and Validation of Different Magnetic Force Microscopy Calibration Schemes (Small 11/2020)

Small ◽  
2020 ◽  
Vol 16 (11) ◽  
pp. 2070058
Author(s):  
Héctor Corte‐León ◽  
Volker Neu ◽  
Alessandra Manzin ◽  
Craig Barton ◽  
Yuanjun Tang ◽  
...  
Keyword(s):  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Force Microscopy
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