Skip to main content Accessibility help

Lorentz Transmission Electron Microscopy Image Simulations of Experimental Nano-Chessboard Observations in Co-Pt Alloys

  • Isha Kashyap (a1), Yongmei M. Jin (a2), Eric P. Vetter (a3), Jerrold A. Floro (a3) and Marc De Graef (a1)...


The magnetization configuration of a novel nano-chessboard structure consisting of L10 and L12 phases in a Co40Pt60 alloy is investigated using Lorentz transmission electron microscopy (LTEM) and micro-magnetic simulations. We show high-resolution LTEM images of nano-size magnetic features acquired through spherical aberration correction in Lorentz Fresnel mode. Phase reconstructions and LTEM image simulations are carried out to fully understand the magnetic microstructure. The experimental Fresnel images of the nano-chessboard structure show zig-zag shaped magnetic domain walls at the inter-phase boundaries between L10 and L12 phases. A circular magnetization distribution with vortex and anti-vortex type arrangement is evident in the phase reconstructed magnetic induction maps as well as simulated maps. The magnetic contrast in experimental LTEM images is interpreted with the help of magnetic induction maps simulated for various relative electron beam-sample orientations inside the TEM.


Corresponding author

Author for correspondence: Marc De Graef, E-mail:


Hide All

Cite this article: Kashyap I, Jin YM, Vetter EP, Floro JA and De Graef M (2018) Lorentz Transmission Electron Microscopy (TEM) Image Simulations of Experimental Nano-Chessboard Observations in Co-Pt Alloys. Microsc Microanal. doi: 10.1017/S143192761800034X



Hide All
Aharonov, Y Bohm, D (1959) Significance of electromagnetic potentials in the quantum theory. Phys Rev 115, 485491.
Beleggia, M Zhu, Y (2003) Electron-optical phase shift of magnetic nanoparticles, Part I: Basic concepts. Philos Mag 83, 10451057.
Beleggia, M, Zhu, Y, Tandon, S De Graef, M (2003) Electron-optical phase shift of magnetic nanoparticles, Part II: Polyhedral particles. Philos Mag 83, 11431161.
Budruk, A, Phatak, C, Petford-Long, AK De Graef, M (2011) In situ Lorentz TEM magnetization study of a Ni-Mn-Ga ferromagnetic shape memory alloy. Acta Mater 59, 48954906.
Chess, JJ, Montoya, SA, Harvey, TR, Ophus, C, Couture, S, Lomakin, V, Fullerton, EE McMorran, BJ (2017) Streamlined approach to mapping the magnetic induction of skyrmionic materials. Ultramicroscopy 177, 7883.
De Graef, M (2000) Chapter 2: Lorentz microscopy: Theoretical basis and image simulations. In Magnetic Microscopy and Its Applications to Magnetic Materials, Experimental Methods in the Physical Sciences, Vol. 36. De Graef M & Zhu Y (Eds.), pp. 27–67. San Diego, CA: Academic Press.
De Graef, M (2003) Introduction to Conventional Transmission Electron Microscopy. Cambridge, UK: Cambridge University Press.
Ghatwai, P (2015) Structure-Property Relationships in Ordered Co-Pt Alloys of Near-Eutectoid Compositions. PhD Thesis. University of Virginia.
Hubert, A Schafer, R (2009) Magnetic Domains: The Analysis of Magnetic Microstructures. Berlin, Germany: Springer.
Humphrey, E De Graef, M (2013) On the computation of the magnetic phase shift for magnetic nano-particles of arbitrary shape using a spherical projection model. Ultramicroscopy 129, 3641.
Humphrey, E, Phatak, C, Petford-Long, AK De Graef, M (2014) Separation of electrostatic and magnetic phase shifts using a modified transport-of-intensity equation. Ultramicroscopy 139, 512.
Kashyap, I De Graef, M (2016) Magnetic domain imaging of Ni-Mn-Ga Heusler alloys using Lorentz TEM. Microsc Microanal 22, 17201721.
Kashyap, I, Floro, JA, Jin, YM De Graef, M (2017) Aberration corrected Lorentz microscopy to investigate magnetic domain walls in Co-Pt nano-chessboards. Microsc Microanal 23, 454455.
Le Bouar, Y, Loiseau, A Khachaturyan, A (1998) Origin of chessboard-like structures in decomposing alloys. Theoretical model and computer simulation. Acta Mater 46, 27772788.
Leroux, C, Loiseau, A, Broddin, D Van Tendeloo, G (1991) Electron microscopy study of the coherent two-phase mixtures L10+L12, in Co-Pt alloys. Philos Mag B 64, 5782.
Mansuripur, M (1991) Computation of electron-diffraction patterns in Lorentz electron microscopy of thin magnetic films. J Appl Phys 69, 24552464.
McVitie, S, McGrouther, D, McFadzean, S, MacLaren, DA, O’Shea, KJ Benitez, MJ (2015) Aberration corrected lorentz scanning transmission electron microscopy. Ultramicroscopy 152, 5762.
Nagai, T, Kimoto, K, Inoke, K Takeguchi, M (2017) Real-space observation of nanoscale magnetic phase separation in dysprosium by aberration-corrected Lorentz microscopy. Phys Rev B 96, 100405100409.
Paganin, D Nugent, KA (1998) Noninterferometric phase imaging with partially coherent light. Phys Rev Lett 80, 25862589.
Petford-Long, A De Graef, M (2012) Lorentz microscopy. In Characterization of Materials, Kaufmann L (Ed.), pp. 17871801. Hoboken, NJ: Wiley-VCH.
Phatak, C, Heinonen, O, De Graef, M Petford-Long, A (2016) Nanoscale skyrmions in a nonchiral metallic multiferroic: Ni2MnGa. Nano Lett 16, 41414148.
Prabhat, KC, Mohan, KA, Phatak, C, Bouman, C De Graef, M (2017) 3D reconstruction of the magnetic vector potential using model based iterative reconstruction. Ultramicroscopy 182, 131144.
Vetter, EP, Geng, L, Ghatwai, P, Gilbert, DA, Jin, Y, Soffa, WA Floro, JA (2016) Lengthscale effects on exchange coupling in Co-Pt L10+L12 nanochessboards. APL Mater 4, 096103.
Vetter, EP, Ghatwai, P, Soffa, WA Floro, JA (2015) Evolution of first-order reversal curves during self-assembly of the Co40:2Pt59:8 nano-chessboard structure. IEEE Magnetics Lett 6, 14.
Volkov, VV, Zhu, Y De Graef, M (2002) A new symmetrized solution for phase retrieval using the transport of intensity equation. Micron 33, 411416.
Wang, L, Laughlin, DE, Wang, Y Khachaturyan, AG (2003) Magnetic domain structure of Fe-55 at.%Pd alloy at different stages of atomic ordering. J Appl Phys 93, 79847986.


Lorentz Transmission Electron Microscopy Image Simulations of Experimental Nano-Chessboard Observations in Co-Pt Alloys

  • Isha Kashyap (a1), Yongmei M. Jin (a2), Eric P. Vetter (a3), Jerrold A. Floro (a3) and Marc De Graef (a1)...


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed