Magnetic Compton Profile Measurement of Thin Films

2010 ◽  
Vol 459 ◽  
pp. 11-14 ◽  
Author(s):  
Hiroyuki Nishino ◽  
Ryutaro Yamaki ◽  
Masayoshi Itou ◽  
Yoshiharu Sakurai ◽  
Hiroshi Sakurai ◽  
...  
Keyword(s):  
Thin Films ◽  
Electronic Structure ◽  
Silicon Nitride ◽  
Compton Scattering ◽  
Beam Line ◽  
Profile Measurement ◽  
Compton Profile ◽  
Scattering Experiment ◽  
Vacuum Tubes ◽  
First Time

We have measured magnetic Compton profile of Co/Pd thin films sputtered on a substrate for studying the electronic structure. For the first time, a silicon nitride substrate of 100 nm thickness we used in the magnetic Compton scattering experiment. We have improved vacuum tubes of the Compton beam-line BL08W of SPring-8, and have reduced greatly the background scattering for the Compton profile. We have succeeded in measuring magnetic Compton profile of Co (0.8 nm)/Pd (1.6 nm) 400 nm multilayer.

Electronic Structure of Liquid Mercury Using Compton Scattering Technique

2004 ◽  
Vol 59 (9) ◽  
pp. 543-549 ◽  
Author(s):  
B. L. Ahuja ◽  
M. Sharma ◽  
S. Mathur
Keyword(s):  
Compton Scattering ◽  
Gamma Ray ◽  
High Energy ◽  
Background Correction ◽  
Compton Profile ◽  
Electron Configuration ◽  
Bremsstrahlung Radiation ◽  
Energy Gamma ◽  
Compton Electrons ◽  
First Time

The isotropic Compton profile of mercury has been measured, using 661.65 keV gamma-rays from a 20 Ci 137Cs source. To extract the true experimental Compton line shape, besides the usual systematic corrections we have incorporated for the first time the background correction due to bremsstrahlung radiation generated by photo and Compton electrons. Theoretical computations have been carried out, using the renormalised-free-atom (RFA) for the electron configuration 4f145d106s2 and free electron models. It is found that the present experimental data with bremsstrahlung background correction are in better agreement with the RFA calculations. This work suggests the incorporation of the bremsstrahlung background correction in Compton scattering experiments of heavy materials using high-energy gamma-ray sources.

Electronic Structure in Heavy Fermion Compound UPd2Al3 through Directional Compton Profile Measurement

2019 ◽  
Vol 88 (3) ◽  
pp. 034714
Author(s):  
Akihisa Koizumi ◽  
Yasunori Kubo ◽  
Etsuji Yamamoto ◽  
Yoshinori Haga ◽  
Yoshiharu Sakurai
Keyword(s):  
Electronic Structure ◽  
Heavy Fermion ◽  
Profile Measurement ◽  
Compton Profile ◽  
Heavy Fermion Compound

Compton Scattering from Heavier Metals

1993 ◽  
Vol 48 (1-2) ◽  
pp. 334-342 ◽  
Author(s):  
B. K Sharma
Keyword(s):  
Electronic Structure ◽  
Compton Scattering ◽  
Three Dimensional ◽  
Ion Beams ◽  
Compton Profile ◽  
Good Resolution ◽  
Dimensional Electron ◽  
Electron Momentum ◽  
Momentum Distributions

Abstract The use of Compton scattering in the determination of electronic structure has grown considerably in the last two decades. With the advent of synchrotron radiation it has become possible, even with good resolution, to measure several single-crystal orientations to determine three-dimensional electron momentum distributions. Although most of the earlier work has been directed to low-Z materials, in the last few years medium and high-Z metals have also been investigated with this technique. In this paper we present a review of these studies on heavier metals with particular attention to the difficulties encountered. Compton profile measurements from techniques based on energetic ion beams are also considered briefly.

scholarly journals Spin-resolved momentum densities: probing orbitals in magnetic oxides

2014 ◽  
Vol 70 (a1) ◽  
pp. C1554-C1554
Author(s):  
Jonathan Duffy
Keyword(s):  
Electronic Structure ◽  
Compton Scattering ◽  
Molecular Orbital ◽  
Electronic Structure Calculations ◽  
High Energy ◽  
Compton Profile ◽  
Spin Moment ◽  
Orbital Moment ◽  
Electron Momentum ◽  
Structure Calculations

Studies of spin-resolved electron momentum densities involve the measurement of the so-called magnetic Compton profile. This is a one-dimensional projection of the electron momentum distribution of only those electrons that contribute to the spin moment of a sample. The technique is applicable to ferri- and ferromagnetic materials. Since electrons originating from different atomic orbitals have specific momentum densities, it is often possible to determine the origin of the magnetism present. Typically, interpretation requires the use of electronic structure calculations using molecular orbital and band structure approaches. The profile is obtained experimentally via the inelastic "Compton" scattering of high energy X-rays. For the experiments discussed here, the high energy beamlines at the ESRF and SPring-8 synchrotron X-ray sources were used, where we have a cryomagnet which can provide a sample environment with applied magnetic fields up to 9 Tesla, at temperatures from 1.3K to 600K. In this talk, we discuss our combined experimental and theoretical study of the spin density of the low-dimensional frustrated metamagnet Ca3Co2O6. The spin moment, measured using magnetic Compton scattering, confirms the existence of a large unquenched Co orbital moment (1.310.1 μB). With regards to the orbital occupation, we have performed molecular orbital calculations on the active trigonal CoO6cluster in order to determine which Co 3d orbitals are responsible for the observed electronic and magnetic behaviour and the observed orbital moment, and revealing the existence a oxygen spin moment of approximately 0.9 μB. Electronic structure calculations with a Hubbard U energy term give Compton profiles which are in good agreement with our experimental data. The magnetic Compton profile exhibits oscillations, which are well described, and their frequency in momentum space corresponds to the real-space inter-cobalt site bond length.

New Insights into the Nature of the Band Gap of CuGeO3 Nanoparticles: Synthesis, Electronic Structure, and Optical and Photocatalytic Properties

2019 ◽  
Author(s):  
Victor Y. Suzuki ◽  
Luís Henrique Cardozo Amorin ◽  
Natália H. de Paula ◽  
Anderson R. Albuquerque ◽  
Julio Ricardo Sambrano ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Material Design ◽  
Photocatalytic Properties ◽  
Critical Parameters ◽  
Synthetic Approach ◽  
Microwave Assisted ◽  
Theoretical Approaches ◽  
Nanoparticles Synthesis ◽  
First Time

<p>We report, for the first time, new insights into the nature of the band gap of <a>CuGeO<sub>3</sub> </a>(CGO) nanocrystals synthesized from a microwave-assisted hydrothermal method in the presence of citrate. To the best of our knowledge, this synthetic approach has the shortest reaction time and it works at the lowest temperatures reported in the literature for the preparation of these materials. The influence of the surfactant on the structural, electronic, optical, and photocatalytic properties of CGO nanocrystals is discussed by a combination of experimental and theoretical approaches, and that results elucidates the nature of the band gap of synthetized CGO nanocrystals. We believe that this particular strategy is one of the most critical parameters for the development of innovative applications and that result could shed some light on the emerging material design with entirely new properties.</p> <p><b> </b></p>

Redox Potential - (Electronic) Structure Relationships in 18- and 17-Electron Mononitrile (or Monocarbonyl) Diphosphine Complexes of Re and Fe

2001 ◽  
Vol 66 (1) ◽  
pp. 139-154 ◽  
Author(s):  
M. Fátima C. Guedes Da Silva ◽  
Luísa M. D. R. S. Martins ◽  
João J. R. Fraústo Da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Cyclic Voltammetry ◽  
Electronic Structure ◽  
Binding Sites ◽  
Closed Shell ◽  
Carbonyl Complexes ◽  
Metal Centre ◽  
Pt Electrode ◽  
Metal Site ◽  
Oxidation Potentials ◽  
First Time

The organonitrile or carbonyl complexes cis-[ReCl(RCN)(dppe)2] (1) (R = 4-Et2NC6H4 (1a), 4-MeOC6H4 (1b), 4-MeC6H4 (1c), C6H5 (1d), 4-FC6H4 (1e), 4-ClC6H4 (1f), 4-O2NC6H4 (1g), 4-ClC6H4CH2 (1h), t-Bu (1i); dppe = Ph2PCH2CH2PPh2), or cis-[ReCl(CO)(dppe)2] (2), as well as trans-[FeBr(RCN)(depe)2]BF4 (3) (R = 4-MeOC6H4 (3a), 4-MeC6H4 (3b), C6H5 (3c), 4-FC6H4 (3d), 4-O2NC6H4 (3e), Me (3f), Et (3g), 4-MeOC6H4CH2 (3h); depe = Et2PCH2CH2PEt2), novel trans-[FeBr(CO)(depe)2]BF4 (4) and trans-[FeBr2(depe)2] (5) undergo, as revealed by cyclic voltammetry at a Pt-electrode and in aprotic non-aqueous medium, two consecutive reversible or partly reversible one-electron oxidations assigned as ReI → ReII → ReIII or FeII → FeIII → FeIV. The corresponding values of the oxidation potentials IE1/2ox and IIE1/2ox (waves I and II, respectively) correlate with the Pickett's and Lever's electrochemical ligand and metal site parameters. This allows to estimate these parameters for the various nitrile ligands, depe and binding sites (for the first time for a FeIII/IV couple). The electrochemical ligand parameter show dependence on the "electron-richness" of the metal centre. The values of IE1/2ox for the ReI complexes provide some supporting for a curved overall relationship with the sum of Lever's electrochemical ligand parameter. The Pickett parametrization for closed-shell complexes is extended now also to 17-electron complexes, i.e. with the 15-electron ReII and FeIII centres in cis-{[ReCl(dppe)2]}+ and trans-{FeBr(depe)2}2+, respectively.

A 3 T superconducting magnet for long-run magnetic Compton-scattering experiments

1998 ◽  
Vol 5 (3) ◽  
pp. 937-939 ◽  
Author(s):  
Nobuhiko Sakai ◽  
Hiroshi Ohkubo ◽  
Yasushi Nakamura
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Compton Scattering ◽  
Superconducting Magnet ◽  
Field Direction ◽  
Compton Profile ◽  
Magnetic Field Direction ◽  
Long Run ◽  
Radiation Shields ◽  
The Magnetic Field

A 3 T superconducting magnet has been designed and constructed for magnetic Compton-profile (MCP) measurements with the new capabilities that the magnetic field direction can be altered quickly (within 5 s) and liquid-He refill is not required for more than one week. For the latter capability, two refrigerators have been directly attached to the cryostat to maintain the low temperature of the radiation shields and for the recondensation of liquid He. The system has been satisfactorily operated for over one week.

scholarly journals Microfluidic resonators with two parallel channels for independent sample loading and effective density tuning

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Jungchul Lee ◽  
Faheem Khan ◽  
Thomas Thundat ◽  
Bong Jae Lee
Keyword(s):  
Silicon Nitride ◽  
Potassium Hydroxide ◽  
Laser Doppler Vibrometer ◽  
Effective Density ◽  
Fluidic Channel ◽  
Custom Made ◽  
Sample Density ◽  
Polysilicon Layer ◽  
Parallel Channels ◽  
First Time

ABSTRACTThis paper reports doubly clamped microchannel embedded resonators with two independent and parallel channels integrated for effective sample density tuning for the first time. With the aid of such a unique design, each fluidic channel can be independently accessed thus different liquid samples can be loaded simultaneously. The proposed fluidic resonators are batch fabricated by depositing silicon nitride, polysilicon, and silicon nitride sequentially on top of a set of 4-inch silicon wafers and sacrificing the middle polysilicon layer with potassium hydroxide (KOH). The sacrificial process defines two parallel channels and releases doubly clamped beam resonators simultaneously. In addition, an off-chip vacuum clamp with optical and fluidic access is custom-made to operate each resonator with enhanced quality factor. The microfluidic resonators mounted on the custom vacuum clamp are thoroughly characterized with a laser Doppler vibrometer and used to measure the effective sample density ranging from 395 to 998 kg/m3.

scholarly journals A novel and potentially scalable CVD-based route towards SnO2:Mo thin films as transparent conducting oxides

2021 ◽  
Author(s):  
Tianlei Ma ◽  
Marek Nikiel ◽  
Andrew G. Thomas ◽  
Mohamed Missous ◽  
David J. Lewis
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Mixed Valence ◽  
Chemical Vapour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conducting Oxides ◽  
Valence States ◽  
3 Omega ◽  
First Time

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract

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