Correlations in the electronic structure of half-metallic ferromagnetic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>CrO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>films: An x-ray absorption and resonant photoemission spectroscopy study

Dedkov, Yuriy; Виноградов, А. С.; Fonin, Mikhail; König, Christian; Vyalikh, D. V.; Preobrajenski, Alexei; Krasnikov, Sergey A.; Kleimenov, Evgueni; Nesterov, M. A.; Rüdiger, Ulrich; Молодцов, С. Л.; Güntherodt, G.

doi:10.1103/physrevb.72.060401

Cited by 63 publications

(37 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The peak characteristics fi t well with references in the literature for Cr 2 O 3 . [39][40][41] This is confi rmed by AFM measurements, which clearly show the Cr 2 O 3 crystals on top of the TiO 2 thin fi lm (see Figure S4, Supporting Information). These results in combination with the electrical characterization suggest that Cr segregates mostly at the surface of TiO 2 and does not affect the charge transport across this layer very signifi cantly.…”

Section: Resultsmentioning

confidence: 67%

Role and Optimization of the Active Oxide Layer in TiO₂‐Based RRAM

Regoutz

Gupta

Serb

et al. 2015

Adv Funct Materials

View full text Add to dashboard Cite

TiO2 is commonly used as the active switching layer in resistive random access memory. The electrical characteristics of these devices are directly related to the fundamental conditions inside the TiO2 layer and at the interfaces between it and the surrounding electrodes. However, it is complex to disentangle the effects of film “bulk” properties and interface phenomena. The present work uses hard X‐ray photoemission spectroscopy (HAXPES) at different excitation energies to distinguish between these regimes. Changes are found to affect the entire thin film, but the most dramatic effects are confined to an interface. These changes are connected to oxygen ions moving and redistributing within the film. Based on the HAXPES results, post‐deposition annealing of the TiO2 thin film was investigated as an optimisation pathway in order to reach an ideal compromise between device resistivity and lifetime. The structural and chemical changes upon annealing are investigated using X‐ray absorption spectroscopy and are further supported by a range of bulk and surface sensitive characterisation methods. In summary, it is shown that the management of oxygen content and interface quality is intrinsically important to device behavior and that careful annealing procedures are a powerful device optimisation technique.

show abstract

Section: Resultsmentioning

confidence: 67%

Role and Optimization of the Active Oxide Layer in TiO₂‐Based RRAM

Regoutz

Gupta

Serb

et al. 2015

Adv Funct Materials

View full text Add to dashboard Cite

show abstract

“…So far, there are only a few XPS results that show the metallic nature of the CrO 2 thin films. 6,7 For instance, Chang et al 7 showed the valence band spectrum with a finite intensity in the region of the Fermi level in the synchrotron XPS measurements with a photon energy of 385 eV, close to the energy we used. The present results are in good agreement with their results.…”

Section: Resultsmentioning

confidence: 99%

“…Only a few exceptions have been reported. 6,7 X-ray photoelectron spectroscopy ͑XPS͒ studies of the film surface do not find a metallic Fermi edge while the film shows metallic conductivity. 8 Cheng et al 9 have reported that Cr 2 O 3 , which is an insulator and the most stable phase in chromium oxide binary system, is formed at the surface of CrO 2 thin film.…”

Section: Introductionmentioning

confidence: 99%

Bulk and surface physical properties of a CrO2 thin film prepared from a Cr8O21 precursor

Iwai

Muraoka

Wakita

et al. 2010

Journal of Applied Physics

View full text Add to dashboard Cite

We have prepared a CrO 2 thin film by chemical vapor deposition from a Cr 8 O 21 precursor and studied the bulk and surface physical properties. The CrO 2 thin film is grown on a TiO 2 ͑100͒ substrate by heating of a Cr 8 O 21 precursor and TiO 2 ͑100͒ substrate together in a sealed quartz tube. The prepared film is found from x-ray diffraction analysis to be an ͑100͒-oriented single phase. The magnetization and resistivity measurements indicate that the film is a ferromagnetic metal with a Curie temperature of about 400 K. Cr 3s core-level and valence band photoelectron spectroscopy spectra reveal the presence of a metallic CrO 2 in the surface region of the film. Our work indicates that preparation from a Cr 8 O 21 precursor is promising for obtaining a CrO 2 thin film with the metallic surface.

show abstract

“…31,32 The lineshape for both the 0/5% and 5/0% films shows clear correlation with the octahedral Cr 3+ of the Cr 2 O 3 reference spectrum, with the position of peaks A, B, and C occurring at the same energies, i.e. 578.3, 579.5, and 580.4 eV; the D peak is not as clear as all others, and occurs around at 582.2 eV.…”

Section: Chemical Environmentmentioning

confidence: 95%

Correlation between morphology, chemical environment, and ferromagnetism in the intrinsic-vacancy dilute magnetic semiconductor Cr-doped Ga2Se3/Si(001)

et al. 2011

View full text Add to dashboard Cite

Chromium-doped gallium sesquiselenide, Cr:Ga2Se3, is a member of a new class of dilute magnetic semiconductor exploiting intrinsic vacancies in the host material. The correlation among room-temperature ferromagnetism, surface morphology, electronic structure, chromium concentration and local chemical and structural environments in Cr:Ga2Se3 films grown epitaxially on silicon is investigated with magnetometry, scanning tunneling microscopy, photoemission spectroscopy and x-ray absorption spectroscopy. Inclusion of a few percent chromium in Ga2Se3 results in laminar, semiconducting films that are ferromagnetic at room temperature with a magnetic moment ≥ 4µB/Cr. The intrinsic-vacancy structure of defected-zinc-blende β−Ga2Se3 enables Cr incorporation in a locally octahedral site without disrupting long-range order, determined by x-ray absorption spectroscopy, as well as strong overlap between Cr 3d states and the Se 4p states lining the intrinsic vacancy rows, observed with photoemission. The highest magnetic moment per Cr is observed near the solubility limit of roughly one Cr per three vacancies. At higher Cr concentrations, islanded, metallic films result, with a magnetic moment that depends strongly on surface morphology. The effective valence is Cr 3+ in laminar films, with introduction of Cr 0 upon islanding. A mechanism is proposed for laminar films whereby ordered intrinsic vacancies mediate ferromagnetism.

show abstract

Correlations in the electronic structure of half-metallic ferromagneticCrO2films: An x-ray absorption and resonant photoemission spectroscopy study

Cited by 63 publications

References 21 publications

Role and Optimization of the Active Oxide Layer in TiO₂‐Based RRAM

Role and Optimization of the Active Oxide Layer in TiO₂‐Based RRAM

Bulk and surface physical properties of a CrO2 thin film prepared from a Cr8O21 precursor

Correlation between morphology, chemical environment, and ferromagnetism in the intrinsic-vacancy dilute magnetic semiconductor Cr-doped Ga2Se3/Si(001)

Contact Info

Product

Resources

About

Correlations in the electronic structure of half-metallic ferromagneticCrO2films: An x-ray absorption and resonant photoemission spectroscopy study

Cited by 63 publications

References 21 publications

Role and Optimization of the Active Oxide Layer in TiO2‐Based RRAM

Role and Optimization of the Active Oxide Layer in TiO2‐Based RRAM

Bulk and surface physical properties of a CrO2 thin film prepared from a Cr8O21 precursor

Correlation between morphology, chemical environment, and ferromagnetism in the intrinsic-vacancy dilute magnetic semiconductor Cr-doped Ga2Se3/Si(001)

Contact Info

Product

Resources

About

Role and Optimization of the Active Oxide Layer in TiO₂‐Based RRAM

Role and Optimization of the Active Oxide Layer in TiO₂‐Based RRAM