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1.
《Solid State Communications》1995,96(5):291-296
We have investigated the angular dependence of the magnetic linear dichroism occurring in angle-resolved photoemission (MLDAD) from epitaxial Co films on Cu(001) using unpolarised HeI- and MgKα-radiation. Spectra were taken while rotating the sample about the magnetisation direction for fixed angle between the directions of light incidence and photoelectron collection. We observe a strong dependence of the MLDAD asymmetry on the electron emission direction with respect to the surface normal showing the importance of photoelectron diffraction in MLDAD. 相似文献
2.
O. Zaharko A. Cervellino H.-Ch. Mertins H. Grimmer F. Schäfers D. Arvanitis 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,23(4):441-448
Magnetic circular dichroism (MCD) in X-ray absorption has been measured at the L
2, 3
edges of Fe in ex-situ grown Fe and Fe
0.50
Co
0.48
V
0.02
films by means of the transmission method. A new approach is developed for fitting the observed transmittance, which describes
the resonance lineshapes as (generalized) Fano profiles. Analytical integration of each single resonance allows a more reliable
determination of the orbital and spin magnetic moments based on the MCD sum rules. The results are consistent with an increase
of the Fe spin and orbital magnetic moment in Fe-Co alloys as obtained by other experiments and band structure calculations.
Received 15 August 2000 and Received in final form 11 June 2001 相似文献
3.
C.M. Teodorescu F. Chevrier R. Brochier C. Richter V. Ilakovac O. Heckmann P. De Padova K. Hricovini 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(3):305-313
Interface reaction and magnetism of epitaxially-grown Fe on InAs(100) are studied by core-level photoemission (As 3d and In 4d) and Fe 2p X-ray magnetic circular dichroism using synchrotron radiation. The reactivity of Fe/InAs(100) is relatively low compared
to that of other interfaces involving deposition of 3d metals on III-V semiconductors. As a consequence, we observe a magnetic signal at Fe L2, 3 edges for the lowest thicknesses studied (1 ML). The atomic magnetic moment reaches a value close to that of the bulk α-Fe
(2.2 μ
B) for Fe coverages exceeding 5 ML. A ferromagnetic compound with approximate stoichiometry of FeAs is formed at the interface.
The orbital magnetism represents between 12 and 20% of the total momentum, due to 3d density of states depletion and to crystal-field modification of the electronic levels. These properties make the Fe/InAs(100)
interface very promising for spin-tunneling devices.
Received 4 April 2002 / Received in final form 13 May 2002 Published online 31 July 2002 相似文献
4.
K. Miyamoto K. IoriA. Kimura T. XieM. Taniguchi S. QiaoK. Tsuchiya 《Solid State Communications》2003,128(5):163-166
Co and Mn 2p core absorption (XAS) and X-ray magnetic circular dichroism (XMCD) spectra have been measured for the ferromagnetic ternary alloy Co2MnGe. The observed Co 2p XAS spectrum can be understood on the basis of the unoccupied Co 3d partial density of states, whereas the overall features of the Mn 2p XAS and XMCD spectra have been partly reproduced by the Mn 2p53d6 final state multiplets. We have found that the orbital polarization of the Co 3d and even the Mn 3d states are recognizable, which suggests that a spin-orbit coupling should be taken into account in the energy band structure in order to reproduce the half metallic nature of this alloy. 相似文献
5.
B. Pilawa I. Keilhauer G. Fischer S. Knorr J. Rahmer A. Grupp 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(3):321-330
The magnetic properties of the cyclic compound [Fe6(bicine)6] LiClO4
. 2MeOH are reported. The cluster Fe6(bicine)6 forms an antiferromagnetically coupled ring structure of Fe III ions. The magnetic susceptibility is measured between 2 and 300 K and yields the exchange coupling of J/k
B = - 27.5±0.5 K. The field dependence of the magnetic moment is studied at 3 and 6 K in magnetic fields up to 5 T. The zero-field
splitting of the first excited spin states with S = 2 and 3 are determined by ESR at 94 GHz. The intra-molecular interactions of the Fe III ions are analyzed and the on-site anisotropy of the Fe III due to the ligand-configuration is determined to d /k
B = - 0.633±0.008K.
Received 28 October 2002 / Received in final form 22 February 2003 Published online 20 June 2003
RID="a"
ID="a"e-mail: bernd@piobelix.physik.uni-karlsruhe.de 相似文献
6.
H. -J. Reyher B. Faust M. Maiwald H. Hesse 《Applied physics. B, Lasers and optics》1996,63(4):331-337
The analysis of EPR spectra obtained from iron doped KTaO3 crystals in the as-grown state revealed three dominant iron centers: Fe3+-OI, axial Fe-centers with spinS = 3/2 and rhombic Fe3+. By comparison with data from literature possible assignments for the center withS = 3/2 are discussed. For the rhombic species the temperature dependence of the main parameters of the Spin- Hamiltonian was measured. The result makes it most plausible that only one rhombic iron center exists in KTaO3, in contrast with literature. The understanding of the EPR spectra allows us to assign transitions, observed at very low magnetic fields by optically detected magnetic resonance (ODMR), to this rhombic Fe center. On this basis, the magnetic circular dichroism (MCD) of this defect could be identified using the method of tagged-MCD. This spectrum is compared to the tagged-MCD of Fe3+-O1 and of axial Fe4+ centers, which may be generated metastably by optical charge transfer. Considerably different structures in the MCD spectra of both Fe3+ centers indicate different local surroundings and electronic states.Dedicated to O. F. Schirmer on the occasion of his 60th birthday 相似文献
7.
Junqueira A. C. Dogra R. Carbonari A. W. Saxena R. N. Mestnik-Filho J. Moralles M. 《Hyperfine Interactions》2001,136(3-8):509-513
The perturbed angular correlation (PAC) technique has been used to study the electric field gradient (EFG) in LaCoO3 perovskite. The results are compared with those for LaCrO3, LaFeO3 measured earlier. The PAC probe, 111In → 111Cd, was introduced in the oxide lattice by means of chemical reaction during sample preparation. In the present work, the
temperature dependence of the electric quadrupole interaction parameters, for LaCoO3 was investigated. The resulting systematics of EFG at 111Cd, in La(Cr,Fe,Co)O3 perovskites, reveals a linear dependence with temperature.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
8.
V. Olmos de León F. Wissmann P. Achenbach J. Ahrens H.-J. Arends R. Beck P.D. Harty V. Hejny P. Jennewein M. Kotulla B. Krusche V. Kuhr R. Leukel J.C. McGeorge V. Metag R. Novotny A. Polonski F. Rambo A. Schmidt M. Schumacher U. Siodlaczek H. Ströher A. Thomas J. Weiß M. Wolf 《The European Physical Journal A - Hadrons and Nuclei》2001,12(2):207-215
Differential cross-sections for Compton scattering from the proton have been measured at the MAMI tagged photon facility using
the TAPS setup. The data cover an angular range of θlab
γ = 59°-155° and photon energies ranging from 55 MeV to 165 MeV. Our results are in good agreement with those from previous experiments,
but yield higher precision. Using dispersion relations the proton polarizabilities have been determined to be = [11.9±0.5stat.±1.3syst.±0.3mod.] . 10-4
fm
3 and = [1.2±0.7stat.±0.3syst.±0.4mod.)] . 10-4
fm
3. These results confirm the Baldin sum rule which was re-evaluated to be + = [13.8±0.4] . 10-4
fm
3. We can also conclude that there is no significant additional asymptotic contribution to the backward spin polarizability
γπ beyond the t-channel π0-exchange.
Received: 9 January 2001 / Accepted: 13 February 2001 相似文献
9.
D.L. Peng T.J. Konno K. Wakoh T. Hihara K. Sumiyama 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):329-332
Cluster-cluster coalescence process of monodispersed Co clusters with mean diameter d = 8.5 and 13 nm deposited a plasma-gas-condensation-type cluster beam deposition system was investigated by in situ electrical conductivity measurements and ex situ scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and analyzed by percolation concept. The electrical
conductivity measurement and TEM observation indicated that, below temperature T≈ 100°C, the Co clusters in the assemblies maintain their original structure as deposited at room temperature, while that the inter-cluster
coalescence takes place at T > 100°C, although the size distribution and the interface morphology of the clusters showed no marked change at substrate temperatures
T
s≤200°C.
Received 29 November 2000 相似文献
10.
D. Rudolph D. Weisshaar F. Cristancho J. Eberth C. Fahlander O. Iordanov S. Skoda Ch. Teich O. Thelen H.G. Thomas 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):377-380
The neutron g
9/2 single-particle state in 57Ni has been unambiguously identified in a combined measurement of the linear polarization, angular distribution, and angular
correlation of γ rays following the fusion-evaporation reaction 28Si(32S,2pn)57Ni at a beam energy of 90 MeV. The linear polarization was measured with a Euroball cluster detector and a prototype of an encapsulated six-fold segmented hexaconical Ge-detector. The spin of the 3701 keV
level in 57Ni was confirmed to be I= 9/2 and its parity determined to be positive.
Received: 24 September 1999 / Revised version: 22 October 1999 相似文献
11.
Yu. M. Yarmoshenko T. V. Kuznetsova A. V. Postnikov A. N. Titov S. G. Titova V. V. Fedorenko P. Vilmercati A. Goldoni R. Claessen 《Physics of the Solid State》2008,50(11):2190-2198
This paper reports on the results of the experimental investigation into the angular dependence of the photoemission of the valence band (the angle-resolved photoelectron spectrum) for the Fe1/4TiTe2 single crystal upon excitation with circularly polarized radiation. The angle-resolved photoelectron spectrum is studied in the vicinity of the Γ point of the Brillouin zone in the two directions ΓK and ΓM with the highest symmetry. The measurements are performed in noncoplanar geometry. The circular dichroism in the photoemission angular distribution is observed over the entire ranges of energies and angles. The magnitude of the dichroism depends on the choice of the band, the binding energy, and the polar angle and varies from 0 at the Γ point to 20%. 相似文献
12.
C. McGinley S. Al Moussalami M. Riedler M. Pflughoefft H. Borchert M. Haase A.R.B. de Castro H. Weller T. Möller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):225-228
We describe photoemission results from pure and Sb-doped SnO2 nanoparticles deposited on gold substrates. Photoelectron spectra with synchrotron radiation were recorded for Sn 3d, Sb
3d and O 1s core levels and valence bands in the 500-1200 eV energy range. For pure SnO2 nanoparticles the surface is terminated by an oxygen rich layer with no obvious surface environment for Sn. When doped n-type
with 9.1% or 16.7% Sb, dopant atoms are concentrated near the surface of the nanoparticles. The valence state of the dopant
atoms is predominantly SbV. Plasmon satellite features are also observed in core level photoemission spectra and their intensity relative to the main
peak increases with increasing photon energy.
Received 30 November 2000 相似文献
13.
Shi-Lin Zhu 《The European Physical Journal A - Hadrons and Nuclei》1999,4(3):277-281
The light cone QCD sum rules are derived for the K
*
Kπ coupling g
K
*
Kπ and the ρππ coupling g
ρππ. The contribution from the excited states and the continuum is subtracted cleanly through the double Borel transform with
respect to the two external momenta, p
1
2, p
2
2= (p−q)2. Our result g
K
*
Kπ= (8.7 ± 0.5) and g
ρππ= (11.5 ± 0.8) is in good agreement with the experimental value.
Received: 31 July 1998 / Revised version: 20 November 1998 相似文献
14.
We measured geometric and magnetic properties of Co films on the Pd(1 1 1) surface by X-ray photoelectron diffraction (XPD), X-ray magnetic circular dichroism (MCD) at the Co L2,3 edge, and the surface magneto-optical Kerr effect (SMOKE) measurements. Co thin films are found to grow incoherently with fcc island structure on the smooth Pd(1 1 1) substrate. Comparison of MCD and SMOKE measurements of Co thin films grown on rough and smooth Pd(1 1 1) surfaces suggests that perpendicular remnant magnetization and Co orbital moment are enhanced by the rough interface. Pd capping layer also induces perpendicular orbital moment enhancement. These observations indicate the influence of hybridization between Co 3d and Pd 4d at the interface on the magnetic anisotropy. 相似文献
15.
A. Agui A. Asahi J. Sayama M. Mizumaki M. Tanaka T. Osaka 《Journal of magnetism and magnetic materials》2008
Magnetic circular dichroism (MCD) and X-ray absorption spectra (XAS) at the Co L2,3-edge of [Co/Pd]20 and [CoB/Pd]20 multilayered films, which were fabricated at 260 °C with different magnetic layer thicknesses (δ), have been measured. The lineshapes of XAS–MCD show that the electronic state of Co 3d of the films hardly changes even when sputtered at higher temperatures. The expectation values of orbital and spin angular momentum (〈Lz〉 and 〈Sz〉) are estimated using the sum rule, and it is found that 〈Lz〉/〈Sz〉 in δ<0.5 nm is larger than that in δ>0.5 nm. 相似文献
16.
F. Le Blanc L. Cabaret J.E. Crawford S. Essabaa V. Fedoseyev W. Geithner J. Genevey M. Girod R. Horn G. Huber S. Kappertz J. Lassen J.K.P. Lee G. Le Scornet V. Mishin R. Neugart J. Obert J. Oms A. Ouchrif S. Peru J. Pinard H. Ravn B. Roussière J. Sauvage D. Verney 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):49-51
Laser spectroscopy measurements have been carried out on the very neutron-rich tin isotopes with the COMPLIS experimental
setup. Using the 5s
25p
23
P
0 → 5s
25p6s
3
P
1 optical transition, hyperfine spectra of 126-132Sn and 125m, 127m, 129m-131mSn where recorded for the first time. The variation of the mean-square charge radius ( δ〈r
2〉) between these nuclei and nuclear moments of the isomers and the odd isotopes were thus measured. An odd-even staggering
which inverts at A = 130 is clearly observed. This indicates a small appearance of a plateau on the δ〈r
2〉 which has to be confirmed by measuring the isotope shift beyond A = 132.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: leblanc@ipno.in2p3.fr 相似文献
17.
N. Keller J. Mistrík Š. Višňovský D.S. Schmool Y. Dumont P. Renaudin M. Guyot R. Krishnan 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(1):67-73
Orthoferrites present, as bulk materials, reorientation transitions of their magnetic moment alignment at temperatures depending
on the rare-earth (RE) ion. In particular, orthoferrites (REFeO3) with RE = Sm, Dy, present this transition at T
SRT = 443 K and 36 K, respectively. The spectra of the complex Kerr and Faraday angle have been measured on orthoferrite thin
films (RE = Sm, Dy, Y), which were prepared by pulsed laser deposition on amorphous quartz substrates. The obtained spectra
exhibit contributions of both surfaces and interfaces. Propagation effects of the polarized light in the magneto-optical medium
which is interpreted in terms of a simplified theoretical formalism, is also observed. For selected photon energies, temperature
dependent Faraday rotation measurements, , on orthoferrite thin films (RE = Sm, Dy, Y) have been performed. A quite different thermal variation compared to the bulk
magnetization has been observed. Curie temperatures are found to be close to the bulk values or slightly larger by 10 K to
20 K as in the case of DyFeO3 and YFeO3. For RE = Sm and Dy, increases with increasing temperature contrary to the saturation magnetization, passes through a maximum at about 460 K and
vanishes with a T
C of 647±18 K, 695 K for RE = Sm and Dy respectively.
Received 28 July 2000 相似文献
18.
A. Michels J. Weissmüller R. Birringer 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):533-540
Based on a micromagnetics model, we develop a method through which quantitative information on the volume-averaged mean-square
magnetostatic stray field 〈|H
b
d|2〉
v due to non-zero divergences of the magnetization M within the bulk of a ferromagnetic body can be obtained by analysis of magnetic-field-dependent small-angle neutron scattering
data. In the limit of high applied magnetic field H
a, when the direction of M deviates only sligthly from H
a, we have estimated a lower bound for 〈|H
b
d|2〉
v as a function of the external field, and we have applied the method to bulk samples of nanocrystalline electrodeposited Ni
and Co and coarse-grained polycrystalline cold-worked Ni. The root-mean-square magnetostatic stray field, which is inherent
to a particular magnetic microstructure, shows a pronounced field dependence, with values ranging from about 5 to 50mT. Even
at applied fields as large as 1.7T, the quantity μ〈|H
b
d|2〉1/2
v of nanocrystalline Co is still 24mT, which suggests that contributions to the total magnetostatic field originating from
the bulk are significant in nanocrystalline ferromagnets; therefore, 〈|H
b
d|2〉
v cannot be ignored in the interpretation of e.g. measurements of magnetization or spin-wave resonance. A comparison of 〈|H
b
d|2〉
v with the volume-averaged mean-square anisotropy field reveals that both quantities are of comparable magnitude.
Received 25 April 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: anmi@nano.uni.saarland.de 相似文献
19.
D. Sohler Zs. Dombrádi J. Blomqvist J. Cederkäll J. Huijnen M. Lipoglavšek M. Palacz A. Atac C. Fahlander H. Grawe A. Johnson A. Kerek W. Klamra J. Kownacki A. Likar L.-O. Norlin J. Nyberg J. Persson D. Seweryniak G. de Angelis P. Bednarczyk D. Foltescu D. Jerrestam S. Juutinen E. Mäkelä M. de Poli H.A. Roth T. Shizuma Ö. Skeppstedt G. Sletten J. Timár S. Törmänen M. Weiszflog 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):171-175
Excited states of 99Ag were populated via the 50Cr + 58Ni (261 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron detector systems for reaction
channel separation. On the basis of the measured γγ-coincidence relations and angular distribution ratios a significantly
extended level scheme has been constructed up to E
x ∼ 7.8 MeV and I = 35/2. The experimental results were described within the framework of the shell model. Candidates for states fully aligned
in the πg
9/2
-3ν(d
5/2, g
7/2)2 valence configuration space were found at 4109 and 6265 keV.
Received: 18 June 2002 / Accepted: 11 October 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: sohler@atomki.hu
Communicated by J. ?yst? 相似文献
20.
Th. Pospischil P. Bartsch D. Baumann R. Böhm K. Bohinc M. Ding S. Derber M.O. Distler D. Elsner I. Ewald J. Friedrich J.M. Friedrich S. Grözinger S. Hedicke P. Jennewein J. Jourdan M. Kahrau F. Klein K.W. Krygier J. Lac A. Liesenfeld S. Malov J. McIntyre H. Merkel P. Merle U. Müller R. Neuhausen M. Potokar R.D. Ransome D. Rohe G. Rosner J. Sanner H. Schmieden M. Seimetz S. Širca I. Sick O. Strähle A. Süle A. Wagner Th. Walcher M. Weis 《The European Physical Journal A - Hadrons and Nuclei》2001,12(1):125-127
The polarization transfer from longitudinally polarized electrons to protons in the elastic scattering p(
e, e'
p) has been measured around Q2 = 0.4 (GeV/c)2 with the three-spectrometer facility at the Mainz microtron MAMI. From this polarization transfer the ratio G
Ep/(G
Mp/μp) has been determined. The ratio is found to be slightly less than unity in agreement with recent results from other laboratories
and from the Rosenbluth separation of cross-sections measured with unpolarized electrons.
Received: 26 July 2001 / Accepted: 25 September 2001 相似文献