High resolution study of Kβ′ and Kβ1,3 X-ray emission lines from Mn-compounds

Limandri, Silvina P.; Ceppi, S.; Tirao, G.; Stutz, G.; Sánchez, Cristián G.; Riveros, José A.

doi:10.1016/j.chemphys.2009.11.001

Cited by 30 publications

(44 citation statements)

References 42 publications

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“…This implies that the Mn local spin moment has decreased with carrier doping, which could arise as a result of a change in electron density (degree of localization), a change in the number of unpaired 3d electrons localized on the metal ion [15,24], or both. In the present case, where Mn is always in a high-spin configuration, the change in the Mn spin state simultaneously correlates with the change in the net charge and the effective spin on the Mn [19,25]. In order to examine if the change of local spin state is due to a valence state change of Mn, we conducted XAS measurements at the Mn K-edge in (Ba 1-x K x )(Zn 0.85 Mn 0.15 ) 2 As 2 .…”

Section: Resultsmentioning

confidence: 99%

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Hole doping and pressure effects on the II-II-V-based diluted magnetic semiconductor (Ba1−xKx)

et al. 2017

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We investigate doping-and pressure-induced changes in the electronic state of Mn 3d and As 4p orbitals in II-II-V based diluted magnetic semiconductor (Ba 1-x ,K x )(Zn 1-y ,Mn y ) 2 As 2 to shed light into the mechanism of indirect exchange interactions leading to high ferromagnetic ordering temperature (Tc = 230 K in optimally doped samples). A suite of x-ray spectroscopy experiments (emission, absorption and dichroism) show that the emergence, and further enhancement of ferromagnetic interactions with increased hole doping into the As 4p band is accompanied by a decrease in local 3d spin density at Mn sites. This is a result of increasing Mn 3d -As 4p hybridization with hole doping which enhances indirect exchange interactions between Mn dopants and gives rise to induced magnetic polarization in As 4p states. On the contrary, application of pressure suppresses exchange interactions. While Mn Kβ emission spectra show a weak response of 3d state to pressure, clear As 4p band broadening (hole delocalization) is observed under pressure ultimately leading to loss of ferromagnetism concomitant with a semiconductor to metal transition. The pressure response of As 4p and Mn 3d states is intimately connected with the evolution of the As-As interlayer distance and the geometry of the MnAs 4 tetrahedral units, which we probed with X-ray diffraction. Our results indicate that hole doping increases the degree of covalency between the anion (As) p states and cation (Mn) d states in the MnAs 4 tetrahedron, a crucial ingredient to promote indirect exchange interactions between Mn dopants and high Tc ferromagnetism. The instability of ferromagnetism and semiconducting state against pressure is mainly dictated by delocalization of anion p states. IntroductionSince the discovery of carrier-mediated ferromagnetism in Mn-doped InAs and GaAs compounds, diluted magnetic semiconductors (DMS) have received extensive attention due to their potential for manipulation of electron spin as a foundation of semiconductor spintronics [1][2][3][4][5]. Much progress has been made in the control of the exchange interactions, in which the magnetic phase can be turned on and off by applying electric field, light irradiation, or external pressure [6]. However, a microscopic understanding of the physical properties of DMS is still limited, e.g., the mechanism leading to magnetic ordering of dopants remains strongly debated [5,7]. Similarly, applications of high-Tc DMS in devices are yet to be realized. In the Mn-doped III-V semiconductors, substitution of trivalent cation Ga for Mn simultaneously introduces an acceptor and a source of magnetic moments. This dual role of Mn complicates theoretical understanding. Recently, Mn-doped II-II-V based semiconductor Ba(Zn,Mn) 2 As 2 was shown to become a high Tc

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Section: Resultsmentioning

confidence: 99%

“…5]. The Kβ spectra for Mn were fitted using three Gaussian functions representing the Kβ′, Kβ x and Kβ 1,3 peaks, and a linear background was subtracted [25]. Derived parameters of ΔE′and I-Kβ′(Kβ′peak intensity relative to the total intensity of the main Kβ region) are displayed in the insets of Figure 5.…”

Section: Resultsmentioning

confidence: 99%

Hole doping and pressure effects on the II-II-V-based diluted magnetic semiconductor (Ba1−xKx)

et al. 2017

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“…[32] Formation of MnKβ′, MnKβ″, and MnKβ x satellites involves the shells of the other elements chemically bound with manganese; therefore, the intensity of these satellites depends on both valence state of manganese and its speciation. [33][34][35] The dependence of chemical shift and relative intensity of MnKβ 5 line and MnKβ′ and MnKβ″ satellites on manganese valence state was shown for some compounds. [15,33,[36][37][38][39] Some methods are proposed to define the valence state of manganese in mineral samples, based on the analysis of К-series spectra of X-ray emission spectra.…”

Section: Introductionmentioning

confidence: 99%

X-ray fluorescence determination of the manganese valence state and speciation in manganese ores

et al. 2015

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a This work concerns determination of the manganese valence state and speciation by wavelength-dispersive X-ray fluorescence analysis. The authors investigated the effect of the manganese valence state and speciation on the intensity of some К-series lines of the X-ray emission spectrum for the samples of manganese compounds. The intensities of MnKβ 5 line and MnKβ′ satellite are least influenced by speciation, and they may be used for evaluating the manganese valence state for the samples containing low iron. The intensities of MnKβ″ and MnKβ x satellites may be employed for assessing the manganese speciation. The results of X-ray fluorescence determination of the manganese valence state and speciation in the manganese ores of the South Ural deposits agree with the X-ray diffraction data. The X-ray fluorescence method is definitely advantageous, because it does not require a complicated process of sample preparation and allows to receive fast information on the manganese valence state and speciation with the purpose to assess the quality of manganese ores.

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“…On the other hand, the measurement of cross sections for low probability phenomena, for example multiple-ionization processes, has deserved the attention and effort of several researchers [11][12][13][14][15], in view of their application to the description of the x-ray emission spectrum. Particularly, the production of satellite lines (arising by either molecular transitions or multiple ionizations) is important in analytical techniques based on x-ray emission: their correct prediction and measurement can be applied to compound speciation and to the validation of molecular orbital theories [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Experimental determination of multiple ionization cross sections in Si by electron impact

et al. 2015

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The thin sample method is often used to experimentally determine ionization cross sections, especially when focusing on the low overvoltage region. The simplicity of the formalism involved in this method is very appealing, but some experimental complications arise in the preparation of thin films. In this work, a thick sample method was used to measure the Si-K x-ray production cross section by electron impact. The good agreement between the results obtained and the values reported in the literature validates the method and the parameters used. The advantages and disadvantages of the method are discussed and its application is extended to the determination of Si multiple-ionization cross sections, where the very low emission rates (around two orders of magnitude lower than the single-ionization case) make the use of the thin sample method impracticable.

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High resolution study of Kβ′ and Kβ1,3 X-ray emission lines from Mn-compounds

Cited by 30 publications

References 42 publications

Hole doping and pressure effects on the II-II-V-based diluted magnetic semiconductor (Ba1−xKx)

Hole doping and pressure effects on the II-II-V-based diluted magnetic semiconductor (Ba1−xKx)

X-ray fluorescence determination of the manganese valence state and speciation in manganese ores

Experimental determination of multiple ionization cross sections in Si by electron impact

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