共查询到20条相似文献,搜索用时 15 毫秒
1.
Ryo Masuda Yasuhiro Kobayashi Shinji Kitao Masayuki Kurokuzu Makina Saito Yoshitaka Yoda Takaya Mitsui Makoto Seto 《Hyperfine Interactions》2016,237(1):43
Synchrotron-radiation (SR) based Mössbauer absorption spectroscopy of various nuclides is reviewed. The details of the measuring system and analysis method are described. Especially, the following two advantages of the current system are described: the detection of internal conversion electrons and the close distance between the energy standard scatterer and the detector. Both of these advantages yield the enhancement of the counting rate and reduction of the measuring time. Furthermore, SR-based Mössbauer absorption spectroscopy of 40K, 151Eu, and 174Yb is introduced to show the wide applicability of this method. In addition to these three nuclides, SR-based Mössbauer absorption spectroscopy of 61Ni, 73Ge, 119Sn, 125Te, 127I, 149Sm, and 189Os has been performed. We continue to develop the method to increase available nuclides and to increase its ease of use. The complementary relation between the time-domain method using SR, such as nuclear forward scattering and the energy-domain methods such as SR-based Mössbauer absorption spectroscopy is also noted. 相似文献
2.
D.L. Nagy L. Bottyán L. Deák E. Szilágyi H. Spiering J. Dekoster G. Langouche 《Hyperfine Interactions》2000,126(1-4):353-361
Grazing incidence nuclear resonant scattering of synchrotron radiation can be applied to perform depth-selective phase analysis
and to determine the isotopic and magnetic structure of thin films and multilayers. Principles and recent experiments of this
new kind of reflectometry are briefly reviewed. Methodological aspects are discussed. Model calculations demonstrate how the
orientations of the sublattice magnetisation in ferro- and antiferromagnetic multilayers affect time-integral and time-differential
spectra. Experimental examples show the efficiency of the method in investigating finite-stacking, in-plane and out-of-plane
anisotropy and spin-flop effects in magnetic multilayers.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Cation distributions and related order-disorder phenomena in the naturally occurring Mn-spinels: iwakiite, galaxite and franklinite, have been investigated by means of57Fe Mössbauer spectroscopy. Previous measurements on an iwakiite sample indicated the existence of Mn-rich and Mn-poor regions. This interpretation has been confirmed in this investigation by further measurements on annealed iwakiite samples. The57Fe Mössbauer spectrum of galaxite from Bald Knob, NC, is a well-resolved quadrupole doublet and indicates the presence of a single crystallographic Fe3+ species. A galaxite sample from Thailand exhibited a complex spectrum of Fe2+ and Fe3+ quadrupole doublets: This sample has been misidentified and should be regarded as a member of the (Mg, Fe)(Al, Fe)2O4 series. The57Fe hyperfine parameters of a rare franklinite from Längban, Sweden, are very close to those for synthetic zinc ferrite, confirming electron microprobe results of an unusually high zinc content. 相似文献
4.
Jitendra Pal Singh R. C. Srivastava H. M. Agrawal R. P. S. Kushwaha 《Hyperfine Interactions》2008,183(1-3):221-228
Nanosize zinc ferrite particles, prepared by nitrate method, were investigated by XRD, TEM, 57Fe Mössbauer spectroscopy and VSM. The average particle size in this system varies from 10 to 62 nm as the sintering temperature increases from 300°C to 1,000°C. The lattice parameters in this system are almost constant at a value of ~8.41 Å. The Mössbauer spectra of all the sintered samples show a single doublet. The Mössbauer hyperfine parameters show little change with the change of sintering temperature. The doublets are ascribed to the presence of superparamagnetism in this system, which is also corroborated by the VSM measurements. 相似文献
5.
I. Presniakov V. Rusakov A. Sobolev A. Gapochka M. Matsnev A. A. Belik 《Hyperfine Interactions》2014,226(1-3):41-50
The present work reports results of the 57Fe Mössbauer measurements on AgFeO2 powder sample recorded at various temperatures including the points of both magnetic phase transitions. The 57Fe Mössbauer spectra of AgFeO2 measured in the paramagnetic range (T > T N1) consist of one quadrupole doublet with rather high quadrupole splitting of Δ300K = 0.66 ± 0.01 mm/s for Fe3+ ions. In order to predict the sign of electric field gradient (EFG) at 57Fe nuclei, we calculated the lattice contribution to the electric field gradient (EFG) at 57Fe nuclei, which emphasized the importance of the dipolar contributions, with resultant oxygen polarizabilities in the range of α O = 0.83 Å3, in agreement with the results obtained previously for other delafossite-like oxides. In the temperature range of T N2 < T < T N1, Mössbauer spectra gave clear evidence for the existence of a distribution of the hyperfine magnetic fields H hf at 57Fe nuclei. We present the results of a model fitting of the spectra based on an assumption of the cycloid magnetic structure of AgFeO2 at T < T N2. The obtained data were analysed in comparison with published data on Mössbauer studies of oxide multiferroics. 相似文献
6.
We built a Debye-Scherrer type powder diffractometer with a57Co radiation source and a large-angle position-sensitive detector. We tuned the incident -ray beam on and off the Mössbauer effect resonance, and measured diffraction patterns from our textured samples of polycrystalline57Fe. Mössbauer effect diffraction dominated over X-ray diffraction for the higher order Bragg peaks. 相似文献
7.
I. Felner I. Nowik S. Balamurugan E. Takayama-Muromachi 《Hyperfine Interactions》2008,184(1-3):111-115
57Fe (1%) doped SrCoO3 obtained by high-pressure method, has been investigated by magnetization and Mössbauer spectroscopy studies (MS) in the temperature range 4.2 K to 300 K. The ferromagnetic ordering temperature T C obtained is 272(2) K. Isothermal magnetization curves have been measured at various temperatures, from which the saturation moments (M sat) have been deduced. The 57Fe MS spectra display standard six-line patterns with an isomer shift typical of Fe3?+? and a very small quadrupole splitting (QS = 0.14(1) mm/s above T C). The magnetic hyperfine field at 4.2 K is 276(1) kOe. The temperature dependencies of the iron hyperfine field and M sat (1.83 µ B at 5 K) are almost identical. This shows that the Fe3?+? is replacing Co4?+?, both of the same electronic configuration. They also interact similarly, namely the Fe–Co exchange is almost identical to the Co–Co exchange. 相似文献
8.
The Mössbauer effect has been studied in the mixed ferrites Co
x
Fe3–x
O4 (forx=0.8, 0.9 and 1) with the spinel structure in the temperature range between 78 and 380 K. The composition withx=1, showed an expected Zeeman spectrum with two overlapping magnetic hyperfine patterns related to the Fe3+ ions in tetrahedral and octahedral sites. While for samples withx=0.8 and 0.9 the Mössbauer spectrum for each compound was successfully analysed into three different patterns corresponding to the ferric ions placed at the tetrahedral and octahedral sites and ferrous ions at the octahedral sites, indicating no electron transfer between Fe3+ and Fe2+, where the quantity of cobalt is sufficiently large to be located at the six nearest neighbours to ferrous ions. The Mössbauer effect parameters were calculated for these observed sites and their variation with temperature reported. The reduced hyperfine magnetic fields of the Fe3+ (B) ions were found to follow the Brillouin curve forS=5/2 and one third power law. The magnetic ordering temperature was determined to be 815 K and the possible magnetic interactions were discussed. 相似文献
9.
Mössbauer absorbtion spectra of57Fe-doped NaCl crystal were measured and correlated with an adequate electric field gradient computation to describe the dipolar complexes occuring at the decay of Suzuki-phase under thermal treatment and X-ray irradiation. An electrostatic potential of the type
was taken into account in the evaluation of EFG tensor. 相似文献
10.
11.
S. Tsutsui M. Nakada Y. Kobayashi S. Nasu Y. Haga Y. Ōnuki 《Hyperfine Interactions》2001,133(1-4):17-21
We have performed 57Fe and 238U Mössbauer measurements of UFe2 in order to investigate its magnetic properties. From the results of 57Fe Mössbauer spectroscopy, the ferrromagnetic ordering at 167 K is caused by the iron 3d-electrons, which hybridize strongly with the uranium 5f-conduction electrons. It is also clarified from the results of 238U Mössbauer spectroscopy that there are no magnetic moments on the uranium atoms. 相似文献
12.
K. Bharuth-Ram H. P. Gunnlaugsson G. Weyer R. Mantovan D. Naidoo R. Sielemann M. Fanciulli G. Langouche S. Olafsson Th. Aigne 《Hyperfine Interactions》2009,193(1-3):115-120
The metastable 2S state in muonic hydrogen is particularily interesting because a measurement of the Lamb shift could reduce the uncertainty in the proton charge radius by an order of magnitude. The most important prerequisite for such a measurement is a sufficiently large population and lifetime of the 2S state. We have determined the long-lived and short-lived 2S population, the deexcitation mechanisms and lifetimes, and the cascade time in μp. 相似文献
13.
K. Bharuth-Ram H. P. Gunnlaugsson R. Mantovan V. V. Naicker D. Naidoo R. Sielemann G. Weyer Th. Aigne 《Hyperfine Interactions》2008,184(1-3):207-211
Our investigations on substitutional and interstitial Fe in the group IV semiconductors, from 57Fe Mössbauer measurements following 57Mn implantation, have been continued with investigations in 3C-SiC. Mössbauer spectra were collected after implantation and measurement at temperatures from 300 to 905 K. Following comparison with Mössbauer parameters for Fe in Si, diamond and Ge, four Fe species are identified: two due to Fe in tetrahedral interstitial sites surrounded, respectively, by four C atoms (Fei.C) or four Si atoms (Fei,Si) and two to Fe in (or close to) defect free or implantation damaged substitutional sites. An annealing stage at 300–500 K is evident. Above 600 K the Fei,Si fraction decreases markedly, reaching close to zero intensity at 905 K. This is accompanied by a corresponding increase in the Fei,C fraction. 相似文献
14.
15.
H. Masenda D. Naidoo K. Bharuth-Ram H. P. Gunnlaugsson G. Weyer W. B. Dlamini R. Mantovan R. Sielemann M. Fanciulli T. E. M?lholt S. ólafsson G. Langouche K. Johnston the ISOLDE Collaboration 《Hyperfine Interactions》2010,198(1-3):15-22
Ion implantation provides a precise method of incorporating dopant atoms in semiconductors, provided lattice damage due to the implantation process can be annealed and the dopant atoms located on regular lattice sites. We have undertaken 57Fe emission Mössbauer spectroscopy measurements on GaAs and GaP single crystals following implantation of radioactive 57Mn?+? ions, to study the lattice sites of the implanted ions, the annealing of implantation induced damage and impurity–vacancy complexes formed. The Mössbauer spectra were analyzed with four spectral components: an asymmetric doublet (D1) attributed to Fe atoms in distorted environments due to implantation damage, two single lines, S1 assigned to Fe on substitutional Ga sites, and S2 to Fe on interstitial sites, and a low intensity symmetric doublet (D2) assigned to impurity–vacancy complexes. The variations in the extracted hyperfine parameters of D1 for both materials at high temperatures (T?> 400 K) suggests changes in the immediate environment of the Fe impurity atoms and different bonding mechanism to the Mössbauer probe atom. The results show that the annealing of the radiation induced damage is more prominent in GaAs compared to GaP. 相似文献
16.
The performance of proposed antihydrogen spectroscopy or gravity experiments will crucially depend on the temperature of the initial antihydrogen sample. Measurements by ATRAP and ATHENA have shown that antihydrogen produced with the nested-trap technique is much hotter than the temperature of the surrounding trap. Therefore, novel schemes for antihydrogen recombination as well as for the pre-cooling of antiprotons are being considered. We are investigating a possible antiproton cooling technique based on the laser cooling of negative osmium ions. If demonstrated to be successful, it will allow the sympathetic cooling of antiprotons—or any negatively charged particles—to microkelvin temperatures. As a first milestone toward the laser cooling of negative ions, we have performed collinear laser spectroscopy on negative osmium and determined the transition frequency and the cross-section of the relevant bound–bound electric-dipole transition. 相似文献
17.
Soft magnetic nanocrystalline alloys have attracted great fundamental interest in recent years due to their two-phase structural and magnetic behaviour. We review first the reliability of the fitting procedures of spectra obtained by 57Fe Mössbauer spectrometry which is a very efficient tool to investigate such materials. Then, we report the common features which characterise the temperature dependence of Mössbauer spectra; the hyperfine field temperature dependence of both the crystalline grains and the intergranular phase is discussed for different crystalline fractions in order to model the magnetic behaviour of the nanocrystalline alloys. 相似文献
18.
With the advent of Fe–As based superconductivity it has become important to study how superconductivity manifests itself in details of 57Fe Mössbauer spectroscopy of conventional, Fe-bearing superconductors. To this end, the iron-based superconductor Lu2Fe3Si5 has been studied by 57Fe Mössbauer spectroscopy over the temperature range from 4.4 K to room temperature with particular attention to the region close to the superconducting transition temperature (Tc=6.1 K). Consistent with the two crystallographic sites for Fe in this structure, the observed spectra appear to have a pattern consisting of two doublets over the whole temperature range. The value of Debye temperature was estimated from temperature dependence of the isomer shift and the total spectral area and compared with the specific heat capacity data. Neither abnormal behavior of the hyperfine parameters at or near Tc, nor phonon softening were observed. 相似文献
19.
High-purity Fe powder was mechanically milled under argon at ambient temperature using an SPEX 8000 mill. The local atomic and magnetic structure was studied using57Co/Fe Mössbauer and111In/Cd perturbed angular correlations (PAC) spectroscopies. After 32 hours of milling, X-ray diffraction revealed effective grain diameters of 18 nm and energy-dispersive X-ray analysis indicated a Cr impurity concentration of 5%, presumably introduced by mechanical attrition of steel ball bearings used for milling. In addition to a spectral component very similar to bulk iron metal, the Mössbauer spectra exhibited hyperfine field shifts attributed to the Cr impurities. PAC spectra on Fe milled for 5 h, with no contamination, exhibited two components: (1) A slightly broadened magnetic interaction attributed to interior, defect-free sites of In/Cd probes with a mean hyperfine field slightly greater than in macroscopic grains. The defect-free site fraction grew appreciably during milling, even though In is essentially insoluble in Fe. (2) An indistinct signal due to mixed magnetic and quadrupole interactions attributed to probes at surface or other defect sites. 相似文献
20.
《Solid State Communications》1987,63(7):587-590
Mössbauer studies have been performed between 6 K and 300 K on single crystals of 57Fe-doped K0.30MoO3, which show a Peierls transition at 180 K towards on incommensurate charge density wave state. The spectra show three doublets. A strong line broadening below 120 K indicates that the Fe impurities are strong pinning centers for the charge density wave above ∼ 120 K and become progressively weak pinning ones below, in agreement with theoretical models. 相似文献