Origination of electron magnetic chiral dichroism in cobalt-doped ZnO dilute magnetic semiconductors

Zhang, Z.H.; Tao, Hualong; He, Ming; Li, Quan

doi:10.1016/j.scriptamat.2011.05.013

Cited by 11 publications

(9 citation statements)

References 13 publications

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“…From the time of its discovery, EMCD has seen a continuous rise and researchers have put serious efforts to improve the signal to noise (S/N) ratio [5][6][7][8][9] and the spatial resolution [10][11][12][13][14][15] of the technique. This led the EMCD technique to explore many materials based problems [16][17][18][19][20][21] as well as to obtain the magnetic signals from single atomic planes [22,23].…”

Section: Introductionmentioning

confidence: 99%

“…From the time of its discovery, EMCD has seen a continuous improvement in the signal to noise (S/N) ratio [5][6][7][8][9][10] , the spatial resolution [11][12][13][14][15][16] and the quantitative analysis. The technique has also been applied to explore material based questions such as interfacial magnetism 17,18 , magnetocrystalline anisotropy 19 , properties of dilute magnetic semiconductors 20 and rare earth magnets 21 . Recently EMCD signals with single atomic plane resolution were achieved 22,23 .…”

mentioning

confidence: 99%

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Simultaneous mapping of EMCD signals and crystal orientations in a transmission electron microscope

Ali

Rusz

Warnatz

et al. 2021

Sci Rep

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When magnetic properties are analysed in a transmission electron microscope using the technique of electron magnetic circular dichroism (EMCD), one of the critical parameters is the sample orientation. Since small orientation changes can have a strong impact on the measurement of the EMCD signal and such measurements need two separate measurements of conjugate EELS spectra, it is experimentally non-trivial to measure the EMCD signal as a function of sample orientation. Here, we have developed a methodology to simultaneously map the quantitative EMCD signals and the local orientation of the crystal. We analyse, both experimentally and by simulations, how the measured magnetic signals evolve with a change in the crystal tilt. Based on this analysis, we establish an accurate relationship between the crystal orientations and the EMCD signals. Our results demonstrate that a small variation in crystal tilt can significantly alter the strength of the EMCD signal. From an optimisation of the crystal orientation, we obtain quantitative EMCD measurements.

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Simultaneous mapping of EMCD signals and crystal orientations in a transmission electron microscope

Ali

Rusz

Warnatz

et al. 2021

Sci Rep

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“…Theoretical studies provided understanding of the interplay of dynamical diffraction effects and inelastic excitations that give rise to EMCD signal [8,9] and its relation to the ground-state expectation values [10] such as spin and orbital magnetic moments via sum rules [11,12]. Although early adopters have already successfully applied this characterization technique in their research [13][14][15][16][17][18][19], yet, EMCD has not reached a stage of wide adoption as a routine experimental method. The reasons are twofold: (1) the method requires a single-crystalline specimen precisely oriented in a two-beam or three-beam orientation and (2) generally EMCD spectra have often a low signal to noise ratio, which is due to the fact that EMCD needs to be measured aside the Bragg spots.…”

Section: Introductionmentioning

confidence: 99%

Scattering of electron vortex beams on a magnetic crystal: Towards atomic-resolution magnetic measurements

et al. 2014

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Use of electron vortex beams (EVB), that is, convergent electron beams carrying an orbital angular momentum (OAM), is a novel development in the field of transmission electron microscopy. They should allow measurement of element-specific magnetic properties of thin crystals using electron magnetic circular dichroism (EMCD)-a phenomenon similar to the x-ray magnetic circular dichroism. Recently, it has been shown computationally that EVBs can detect magnetic signal in a scanning mode only at atomic resolution. In this follow-up work, we explore in detail the elastic and inelastic scattering properties of EVBs on crystals, as a function of beam diameter, initial OAM, acceleration voltage, and beam displacement from an atomic column. We suggest that for a 10-nm layer of bcc iron oriented along (001) zone axis, an optimal configuration for a detection of EMCD is an EVB with OAM of 1 and a full width at half maximum diffraction-limited beam diameter of 1.6Å, acceleration voltage 200 kV, and an annular detector with inner and outer radii of 7 and 44 mrad, respectively.

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“…Among the experimental techniques available for characterization of nanostructured materials, aberration corrected scanning transmission electron microscopy (STEM), in combination with electron energy loss spectroscopy (EELS), is a powerful technique for structural and chemical analysis down to the atomic scale. Energy-loss magnetic circular dichroism (EMCD) can be measured in a TEM studying the L 2,3 EELS absorption edges of transition metal, which has already been used to study nanostructured materials in the subnanometer range (Schattschneider et al, 2008;Zhang et al, 2009Zhang et al, , 2011Lidbaum et al, 2010;Carretero-Genevrier et al, 2012;Salafranca et al, 2012). Furthermore, as has recently been demonstrated by Schattschneider et al (2006) electron probes can also be used to study the magnetic properties.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, as has recently been demonstrated by Schattschneider et al (2006) electron probes can also be used to study the magnetic properties. Energy-loss magnetic circular dichroism (EMCD) can be measured in a TEM studying the L 2,3 EELS absorption edges of transition metal, which has already been used to study nanostructured materials in the subnanometer range (Schattschneider et al, 2008;Zhang et al, 2009Zhang et al, , 2011Lidbaum et al, 2010;Carretero-Genevrier et al, 2012;Salafranca et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Electronic and Magnetic Structure of LaSr-2×4 Manganese Oxide Molecular Sieve Nanowires

et al. 2014

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In this study we combine scanning transmission electron microscopy, electron energy loss spectroscopy and electron magnetic circular dichroism to get new insights into the electronic and magnetic structure of LaSr-2×4 manganese oxide molecular sieve nanowires integrated on a silicon substrate. These nanowires exhibit ferromagnetism with strongly enhanced Curie temperature (T c >500 K), and we show that the new crystallographic structure of these LaSr-2×4 nanowires involves spin orbital coupling and a mixed-valence Mn3+/Mn4+, which is a must for ferromagnetic ordering to appear, in line with the standard double exchange explanation.

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Origination of electron magnetic chiral dichroism in cobalt-doped ZnO dilute magnetic semiconductors

Cited by 11 publications

References 13 publications

Simultaneous mapping of EMCD signals and crystal orientations in a transmission electron microscope

Simultaneous mapping of EMCD signals and crystal orientations in a transmission electron microscope

Scattering of electron vortex beams on a magnetic crystal: Towards atomic-resolution magnetic measurements

Electronic and Magnetic Structure of LaSr-2×4 Manganese Oxide Molecular Sieve Nanowires

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