Atomic resolution energy-loss magnetic chiral dichroism measurements enabled by patterned apertures

Ali, Hasan,1985-Uppsala universitet,Tillämpad materialvetenskap,Uppsala Univ, Dept Engn Sci, Appl Mat Sci, Electron Microscopy & Nanoengn, Box 534, S-75121 Uppsala, Sweden. (author)

Electron energy-loss magnetic chiral dichroism (EMCD) has the potential to measure magnetic properties of the materials at atomic resolution but the complex distribution of magnetic signals in the zone axis and the overlapping diffraction discs at higher beam convergence angles make the EMCD signal acquisition challenging. Recently, the use of ventilator apertures to acquire the EMCD signals with atomic resolution was proposed. Here we give the experimental demonstration of several types of ventilator apertures and obtain a clear EMCD signal at beam semiconvergence angles of 5 mrad. To simplify the experimental procedures, we propose a modified ventilator aperture which not only simplifies the complex scattering conditions but reduces the influence of lens aberrations on the EMCD signal as compared to the originally proposed ventilator apertures. In addition, this modified aperture can be used to analyze magnetic crystals with various symmetries and we demonstrate this feature by acquiring EMCD signals on different zone axis orientations of an Fe crystal. With the same aperture we obtain EMCD signals with convergence angles corresponding to atomic resolution electron probes. After the theoretical demonstration of the EMCD signal on a zone axis orientation at high beam convergence angles, this work thus overcomes the experimental and methodological hurdles and enables atomic resolution EMCD on the zone axis by using apertures.

Negi, Devendra SinghUppsala universitet,Materialteori,Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden.;Max Planck Inst Solid State Res, Stuttgart Ctr Electron Microscopy, Heisenbergstr 1, D-70569 Stuttgart, Germany.(Swepub:uu)devne912 (author)
Warnatz, TobiasUppsala universitet,Materialfysik,Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden.(Swepub:uu)tobwa484 (author)
Hjörvarsson, BjörgvinUppsala universitet,Materialfysik,Materialteori,Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden.(Swepub:uu)bjorghvs (author)
Rusz, Jan,1979-Uppsala universitet,Materialteori,Teoretisk fysik,Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden.(Swepub:uu)janru887 (author)
Leifer, Klaus,1965-Uppsala universitet,Tillämpad materialvetenskap,Uppsala Univ, Dept Engn Sci, Appl Mat Sci, Electron Microscopy & Nanoengn, Box 534, S-75121 Uppsala, Sweden.(Swepub:uu)kllei839 (author)
Uppsala universitetTillämpad materialvetenskap (creator_code:org_t)

By the author/editor: Ali, Hasan, 1985 ...; Negi, Devendra S ...; Warnatz, Tobias; Hjörvarsson, Bjö ...; Rusz, Jan, 1979-; Leifer, Klaus, 1 ...

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Physical Science ...; and Condensed Matter ...

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