Element-specific characterization of heterogeneous magnetism in (Ga,Fe)N films

Kowalik, I.A.; Persson, Andreas; Niño, Miguel Ángel; Navarro-Quezada, A.; Faina, B.; Bonanni, A.; Dietl, T.; Arvanitis, D.

doi:10.1103/physrevb.85.184411

Cited by 14 publications

(19 citation statements)

References 43 publications

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“…In particular, a strong XMCD eect is visible in the energy of 397 eV, just before the absorption edge, which corresponds to the forbidden energy range within the band gap. This signal is comparable with the results published for GdN and it is about 0.5% of the high energy continuum of the absorption spectrum [47,48]. To compare the two results the spectra are normalized to the high energy continuum.…”

Section: Dilute Magnetic Semiconductorssupporting

confidence: 75%

Element Specific Magnetometry Combining X-ray Circular with Linear Dichroism: Fundamentals and Applications

Kowalik

2015

Acta Phys. Pol. A

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This article gives an overview of the use of X-ray absorption spectroscopy to characterize the magnetic properties for technologically important, low dimensional magnetic materials. An overview is given both for the experimental hardware, the measurements and the analysis of the spectra. The information obtained is discussed for metallic and semiconducting systems, using both the X-ray magnetic circular dichroism and the X-ray linear magnetic dichroism spectroscopy. DOI: 10.12693/APhysPolA.127.831 PACS: 78.70.Dm, 78.20.Ls, 75.50.Pp, 75.50.Tt Short historic overview of the XMCD techniqueTo start this historical outline one should mention that although the X-ray magnetic circular dichroism (XMCD) technique is relatively young, the magneto-optical eect characteristic of the interaction between light and a magnetic medium was studied already in the nineteenth century, when several key discoveries were made enabling the development of new experimental techniques and thus studying so far unknown properties of matter. Let's start with Augustin Fresnel, who was the rst one to envision the existence of circular and elliptical light polarization.In his equations on light waves he described how light polarized in circular or elliptical states can be produced At about the same time, in 1895, investigating the phenomenon of cathode rays Roentgen discovered invisible, high-energy radiation in the spectral range from ultraviolet to gamma rays. This discovery initiated research on the physical properties of X-ray radiation and its interaction with matter. Despite the fact that the discovery of X-rays was made after the discovery of magneto-optical eects, it took still several decades for magneto-optics experiments based on X-rays.The rst theoretical predictions of a strong magnetic circular dichroism eect has been made in 1975 by E.A.(831)

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Section: Dilute Magnetic Semiconductorssupporting

confidence: 75%

Element Specific Magnetometry Combining X-ray Circular with Linear Dichroism: Fundamentals and Applications

Kowalik

2015

Acta Phys. Pol. A

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“…In this study, we compared the experimental XAS and XMCD spectra acquired at Fe L 2,3 and N K-edges of Fe 4 N films with those calculated theoretically, and clarified the element specific local electronic structure in Fe 4 N. To our knowledge, there have been no reports thus far on the theoretical calculation for XAS and XMCD spectra at Fe L 2,3 -edge of Fe 4 N. There is only one report on the line shapes of the XAS and XMCD spectra at N K-edge of Fe 4 N calculated by the first-principles using FEFF code. 26 However, a comparison with experimental results is yet to seek.…”

Section: Introductionmentioning

confidence: 99%

Local electronic states of Fe4N films revealed by x-ray absorption spectroscopy and x-ray magnetic circular dichroism

Ito

Toko

Takeda

et al. 2015

Journal of Applied Physics

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We performed x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements at Fe L2,3 and N K-edges for Fe4N epitaxial films grown by molecular beam epitaxy. In order to clarify the element specific local electronic structure of Fe4N, we compared experimentally obtained XAS and XMCD spectra with those simulated by a combination of a first-principles calculation and Fermi's golden rule. We revealed that the shoulders observed at Fe L2,3-edges in the XAS and XMCD spectra were due to the electric dipole transition from the Fe 2p core-level to the hybridization state generated by σ* anti-bonding between the orbitals of N 2p at the body-centered site and Fe 3d on the face-centered (II) sites. Thus, the observed shoulders were attributed to the local electronic structure of Fe atoms at II sites. As to the N K-edge, the line shape of the obtained spectra was explained by the dipole transition from the N 1s core-level to the hybridization state formed by π* and σ* anti-bondings between the Fe 3d and N 2p orbitals. This hybridization plays an important role in featuring the electronic structures and physical properties of Fe4N.

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“…The resulting attractive force between the magnetic cations may lead to their aggregation, either at the growth surface during the epitaxial process, as in (Ga,Fe)N (Refs. [4][5][6][7] and for Mn cation dimers in (Ga,Mn)As, 8 or by being triggered by appropriate post-growth high-temperature annealing [9][10][11][12] or high-temperature growth, 13 as observed in (Ga,Mn)As [9][10][11][12] and (Ga,In,Mn)As, 13 respectively. Significantly, in a number of systems, the TM-rich nanocrystals that are formed in this way, such as Fe n N (n≥ 1), [4][5][6][7] MnAs 13 or Co, [14][15][16] do not have a uniform distribution in the film.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7] and for Mn cation dimers in (Ga,Mn)As, 8 or by being triggered by appropriate post-growth high-temperature annealing [9][10][11][12] or high-temperature growth, 13 as observed in (Ga,Mn)As [9][10][11][12] and (Ga,In,Mn)As, 13 respectively. Significantly, in a number of systems, the TM-rich nanocrystals that are formed in this way, such as Fe n N (n≥ 1), [4][5][6][7] MnAs 13 or Co, [14][15][16] do not have a uniform distribution in the film. Instead, they tend to accumulate in planes that lie perpendicular to the growth direction, either close to the film surface [4][5][6][7]13 or at its interface with the substrate, [14][15][16] by a process that is referred to as nucleation-controlled aggregation.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Fe-N nanocrystals and nitrogen–containing inclusions in (Ga,Fe)N thin films using transmission electron microscopy

Kovács

Schaffer

Moreno

et al. 2013

Journal of Applied Physics

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Nanometric inclusions filled with nitrogen, located adjacent to Fe n N (n = 3 or 4) nanocrystals within (Ga,Fe)N layers, are identified and characterized using scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). High-resolution STEM images reveal a truncation of the Fe-N nanocrystals at their boundaries with the nitrogencontaining inclusion. A controlled electron beam hole drilling experiment is used to release nitrogen gas from an inclusion in situ in the electron microscope. The density of nitrogen in an individual inclusion is measured to be 1.4 ± 0.3 g/cm 3 . These observations provide an explanation for the location of surplus nitrogen in the (Ga,Fe)N layers, which is liberated by the nucleation of Fe n N (n> 1) nanocrystals during growth.

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Element-specific characterization of heterogeneous magnetism in (Ga,Fe)N films

Cited by 14 publications

References 43 publications

Element Specific Magnetometry Combining X-ray Circular with Linear Dichroism: Fundamentals and Applications

Element Specific Magnetometry Combining X-ray Circular with Linear Dichroism: Fundamentals and Applications

Local electronic states of Fe4N films revealed by x-ray absorption spectroscopy and x-ray magnetic circular dichroism

Characterization of Fe-N nanocrystals and nitrogen–containing inclusions in (Ga,Fe)N thin films using transmission electron microscopy

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