Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-28T07:21:37.720Z Has data issue: false hasContentIssue false

Energy-loss magnetic chiral dichroism (EMCD): Magnetic chiral dichroism in the electron microscope

Published online by Cambridge University Press:  31 January 2011

S. Rubino
Affiliation:
Institute for Solid State Physics, Vienna University of Technology, Vienna A-1040, Austria; and Department of Engineering, Uppsala University, Uppsala S-751 21, Sweden
P. Schattschneider
Affiliation:
Institute for Solid State Physics, Vienna University of Technology, Vienna A-1040, Austria; and Service Centre for TEM, Vienna University of Technology, Vienna A-1040, Austria
M. Stöger-Pollach
Affiliation:
Service Centre for TEM, Vienna University of Technology, Vienna A-1040, Austria
C. Hébert
Affiliation:
SB-CIME Station 12, EPFL, Lausanne, Switzerland
J. Rusz
Affiliation:
Department of Physics, Uppsala University, Uppsala S-751 21, Sweden; and Institute of Physics, Academy of Sciences of the Czech Republic, Prague CZ-18221, Czech Republic
L. Calmels
Affiliation:
Nanomaterieaux Group, CEMES-CNRS, FR-31400 Toulouse, France
B. Warot-Fonrose
Affiliation:
Nanomaterieaux Group, CEMES-CNRS, FR-31400 Toulouse, France
F. Houdellier
Affiliation:
Nanomaterieaux Group, CEMES-CNRS, FR-31400 Toulouse, France
V. Serin
Affiliation:
Nanomaterieaux Group, CEMES-CNRS, FR-31400 Toulouse, France
P. Novak
Affiliation:
Institute of Physics, Academy of Sciences of the Czech Republic, Prague CZ-18221, Czech Republic
Get access

Abstract

A new technique called energy-loss magnetic chiral dichroism (EMCD) has recently been developed [P. Schattschneider, et al. Nature441, 486 (2006)] to measure magnetic circular dichroism in the transmission electron microscope (TEM) with a spatial resolution of 10 nm. This novel technique is the TEM counterpart of x-ray magnetic circular dichroism, which is widely used for the characterization of magnetic materials with synchrotron radiation. In this paper we describe several experimental methods that can be used to measure the EMCD signal [P. Schattschneider, et al. Nature441, 486 (2006); C. Hébert, et al. Ultramicroscopy108(3), 277 (2008); B. Warot-Fonrose, et al. Ultramicroscopy108(5), 393 (2008); L. Calmels, et al. Phys. Rev. B76, 060409 (2007); P. van Aken, et al. Microsc. Microanal.13(3), 426 (2007)] and give a review of the recent improvements of this new investigation tool. The dependence of the EMCD on several experimental conditions (such as thickness, relative orientation of beam and sample, collection and convergence angle) is investigated in the transition metals iron, cobalt, and nickel. Different scattering geometries are illustrated; their advantages and disadvantages are detailed, together with current limitations. The next realistic perspectives of this technique consist of measuring atomic specific magnetic moments, using suitable spin and orbital sum rules, [L. Calmels, et al. Phys. Rev. B76, 060409 (2007); J. Rusz, et al. Phys. Rev. B76, 060408 (2007)] with a resolution down to 2 to 3 nm.

Type
Outstanding Symposium Papers
Copyright
Copyright © Materials Research Society 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Kim, D.H., Fischer, P., Chao, W., Anderson, E., Im, M.Y., Shin, S.C., Choe, S.B.: Magnetic soft x-ray microscopy at 15 nm resolution probing nanoscale local magnetic hysteresis. J. Appl. Phys. 99, 08H303 2006CrossRefGoogle Scholar
2Schütz, G., Wagner, W., Wilhelm, W., Kienle, P., Zeller, R., Frahm, R., Materlik, G.: Absorption of circularly polarized x-rays in iron. Phys. Rev. Lett. 58, 737 1987CrossRefGoogle ScholarPubMed
3Thole, B.T., Carra, P., Sette, F., Laan, G. vander: X-ray circular dichroism as a probe of orbital magnetization. Phys. Rev. Lett. 68, 1943 1992CrossRefGoogle ScholarPubMed
4Chen, C.T., Idzerda, Y.U., Lin, H-J., Smith, N.V., Meigs, G., Chaban, E., Ho, G.H., Pellegrin, E., Sette, F.: Experimental confirmation of the x-ray magnetic circular dichroism sum rules for iron and cobalt. Phys. Rev. Lett. 75, 152 1995CrossRefGoogle ScholarPubMed
5Hitchcock, A.P.: Near edge electron energy loss spectroscopy: Comparison to x-ray absorption. Jpn. J. Appl. Phys. 32(2), 176 1993CrossRefGoogle Scholar
6van Aken, P., Lauterbach, S.: Strong magnetic linear dichroism in Fe L23 and O K electron energy-loss near-edge spectra of antiferromagnetic hematite α-Fe2O3. Phys. Chem. Miner. 30, 469 2003CrossRefGoogle Scholar
7Schattschneider, P., Rubino, S., Hébert, C., Rusz, J., Kuneš, J., Novak, P., Carlino, E., Fabrizioli, M., Panaccione, G., Rossi, G.: Experimental proof of circular magnetic dichroism in the electron microscope. Nature 441, 486 2006CrossRefGoogle Scholar
8Hébert, C., Schattschneider, P., Rubino, S., Novák, P., Rusz, J., Stöger-Pollach, M.: Magnetic circular dichroism in electron energy loss spectrometry. Ultramicroscopy 108(3), 277 2008CrossRefGoogle ScholarPubMed
9Warot-Fonrose, B., Houdellier, F., Hÿtch, M.J., Calmels, L., Serin, V., Snoeck, E.: Mapping inelastic intensities in diffraction patterns of magnetic samples using the energy spectrum imaging technique. Ultramicroscopy 108(5), 393 2008CrossRefGoogle ScholarPubMed
10Calmels, L., Houdellier, F., Warot-Fonrose, B., Gatel, C., Hÿtch, M.J., Serin, V., Snoeck, E., Schattschneider, P.: Experimental application of sum rules for electron energy loss magnetic chiral dichroism. Phys. Rev. B 76, 060409 2007CrossRefGoogle Scholar
11van Aken, P., Gu, L., Goll, D., Schütz, G.: Electron magnetic linear dichroism (EMLD) and electron magnetic circular dichroism (EMCD) in electron energy-loss spectroscopy. Microsc. Microanal. 13(3), 426 2007CrossRefGoogle Scholar
12Rusz, J., Eriksson, O., Novák, P., Oppeneer, P.M.: Sum-rules for electron energy-loss near-edge spectra. Phys. Rev. B 76, 060408 2007CrossRefGoogle Scholar
13Schütz, G., Wienke, R., Wilhelm, W., Wagner, W., Kienle, P., Zeller, R., Frahm, R.: Strong spin-dependent absorption at the L2,3-edges of 5d-impurities in iron. Z. Phys. B 75, 495 1989CrossRefGoogle Scholar
14Lovesey, S.W., Collins, S.P.: X-Ray Scattering and Absorption by Magnetic Materials,, edited by J. Chikawa, J.R. Helliwell, and S.W. Lovesey (Clarendon Press, Oxford, 1996), pp. 120–131CrossRefGoogle Scholar
15Kohl, H., Rose, H.: Theory of image formation by inelastically scattered electrons in the electron microscope. Adv. Electron. Electron Phys. 65, 173 1985CrossRefGoogle Scholar
16Rusz, J., Rubino, S., Schattschneider, P.: First principles theory of chiral dichroism in electron microscopy applied to 3d ferromagnets. Phys. Rev. B 75, 214425 2007CrossRefGoogle Scholar
17Metherell, A.J.F.: in Electron Microscopy In Material Science,, edited by E. Ruedl and U. Valdrè (CEC, Luxembourg, 1975), pp. 397–552Google Scholar
18Kainuma, Y.: The theory of Kikuchi patterns. Acta Crystallogr. 8, 247 1955CrossRefGoogle Scholar
19Morniroli, J.P., Houdellier, F., Roucau, C., Puiggalí, J., Gestí, S., Redjaïmia, A.: LACDIF, a new electron diffraction technique obtained with the LACBED configuration and a Cs corrector: Comparison with electron precession. Ultramicroscopy 108(2), 100 2008CrossRefGoogle Scholar
20Schattschneider, P., Hébert, C., Rubino, S., Stöger-Pollach, M., Rusz, J., Novák, P.: Magnetic circular dichroism in EELS: Towards 10 nm resolution. Ultramicroscopy 108(5), 433 2008CrossRefGoogle ScholarPubMed
21Verbeeck, J., Hébert, C., Rubino, S., Novák, P., Rusz, J., Houdellier, F., Gatel, C., Schattschneider, P.: Optimal aperture sizes and positions for EMCD experiments. Ultramicroscopy 108(9), 865 2008CrossRefGoogle ScholarPubMed
22Hejtmánek, J., Pollert, E., Jirák, Z., Sedmidubský, D., Strejc, A., Maignan, A., Martin, C., Hardy, V., Kužel, R., Tomioka, Y.: Magnetism and transport in Pr1−xSrxMnO3 single crystals (0.48 ⩽ x ⩽ 0.57). Phys. Rev. B 66, 014426 2002CrossRefGoogle Scholar