共查询到20条相似文献,搜索用时 0 毫秒
1.
《Journal of magnetism and magnetic materials》2001,223(3):221-232
Polycrystalline and epitaxial (1 0 0), (1 1 0), and (1 1 1)-oriented Ni3Pt, NiPt, and NiPt3 films were deposited over a range of growth temperatures from 80°C to 700°C. Films grown at moderate temperatures (200–400°C) exhibit growth-induced properties similar to Co–Pt alloys: enhanced and broadened Curie temperature, perpendicular magnetic anisotropy and large coercivity. As in Co–Pt, the magnetic properties suggest a clustering of Ni into platelets on the growth surface, as the films are being grown. Unlike Co–Pt, however, NiPt films exhibit a strong orientational dependence of anisotropy and enhanced Curie temperature, possibly resulting from different types of surface reconstructions which affect the growth surface. 相似文献
2.
R. S. Iskhakov O. A. Bayukov V. A. Seredkin S. V. Stolyar V. Yu. Yakovchuk G. I. Frolov G. V. Bondarenko 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(3):339-342
Amorphous ferrimagnetic Tb x Fe1?x films with perpendicular magnetic anisotropy and Tb x Fe1?x /NiFe exchange-coupled structures characterized by unidirectional anisotropy are obtained. The magnetic and chemical inhomogeneity of alloys of Tb x Fe1?x compensation composition is established on the basis of Mössbauer studies of these systems. 相似文献
3.
We show that a metallic surface state is formed on Tl/Ge(111)-(1 × 1). The surface state forms electron pockets around K of the surface Brillouin zone. A first-principles calculation reveals that the electron pockets are composed of a single branch of a spin-split surface-state band. The spin quantization axis is along the surface normal and inverts according to the time-reversal symmetry. Since this spin-split branch is the unique metallic band on this surface, the surface conductivity should be governed by this spin-split branch, suggesting a possible spin-polarized electric current. 相似文献
4.
《Journal of magnetism and magnetic materials》1987,66(2):175-186
Ground-state magnetic properties of ordered FeRh alloys are discussed by using the realistic canonical d-band model within the Hartree-Fock and coherent potential approximations. Local magnetic moments of Fe and Rh atoms in ferromagnetic and antiferromagnetic FexRh1-x alloys are computed as a function of x, the Fe concentration. Calculated results are in good agreement with the neutron-diffraction data. The band-energy calculation indicates that in Fe-rich alloys excess Fe atoms substituted on Rh sites having larger magnetic moments than Rh atoms, play an important role in the antiferromagnetic to ferromagnetic transition observed at low temperatures. 相似文献
5.
A. S. Ilyushin A. A. Opalenko A. I. Firov E. V. Solodov Z. S. Umkhaeva 《Physics of the Solid State》2014,56(3):501-504
The structural and magnetic characteristics of phase transformations in Tb(Fe1 ? x Al x )2 alloys with concentrations x = 0?0.9 have been measured in the temperature range from 90 to 450 K. The temperature dependences of the hyperfine magnetic fields for each of local configurations of the nearest environment of iron atoms upon substitution of aluminum atoms for iron atoms have been found using Mössbauer spectroscopy. 相似文献
6.
7.
Hangil Lee 《Current Applied Physics》2013,13(5):826-829
The magnetic and structural properties of a series of VxCo1?x alloy films prepared in a variety of compositions on a W(110) surface were investigated using spin-resolved photoemission spectroscopy (SRPES) and low-energy electron diffraction (LEED) measurements. The epitaxial structures of the films were preserved over all V concentrations, despite the observation of a structural phase transition (SPT: hcp/bcc at x = 0.38), which was apparent from the LEED images. A magnetic phase transition (MPT) from ferromagnetic to paramagnetic occurred in the Co-rich region at x = 0.38. The SPT (from hcp and bcc) and MPT (from ferromagnetic to paramagnetic) were clearly correlated at x = 0.38, possibly due to changes in the electronic and magnetic structures of the valence band, as monitored by SRPES and LEED. The magnetization in the VxCo1?x alloy films on a W(110) surface varied systematically with the V concentration, and correlations between the structural changes and magnetic properties were revealed using SRPES and LEED. 相似文献
8.
W. Sänger 《Zeitschrift für Physik B Condensed Matter》1984,55(1):13-16
The isothermal magnetic susceptibility (x) of the completely miscible liquid Pd1–x
Si
x
alloy system shows a rapid monotonous decrease withx from strong paramagnetism to weaklyx-dependent diamagnetism. The measured susceptibility isotherm at 1825 K is analysed within 0x1 by using a semiphenomenological method of decomposing the magnetic susceptibility into its constituent parts. Because of the empirical similarity between liquid and glassy metals this interpretation also provides assertions about the magnetism of glassy Pd1–x
Si
x
aroundx=0.2. 相似文献
9.
《Journal of Electron Spectroscopy and Related Phenomena》1997,83(1):1-7
High-resolution electron energy loss spectroscopy (HREELS) has been used to study stretch vibrations of CO chemisorbed at low coverage on PtxNi1−x(111). Bayesian probability theory along with the entropic prior (Maxent) has been employed to deconvolve the apparatus function and to improve the apparent energy resolution. Maxent has proven very successful in a wide range of inversion problems. Here the resolution enhancement enables the positions of CO on the PtNi surface to be identified. It appears that CO is predominantly on top of Ni with the Ni atoms coordinated threefold laterally and with Ni in linear chains or on top of Pt. Furthermore, the ratio of the Pt to the Ni peak is used to study the dependence of the Pt concentration in the first layer on the annealing temperature. 相似文献
10.
The structural, electronic and magnetic properties of Fe–Co alloy nanowires encapsulated inside zigzag (10,0) boron nitride nanotube (BNNT) are investigated by ab initio calculations. Similar to pristine nanotube, the opposite directional relaxations for the N atoms (move outwards) and B atoms (move inwards) from their initial positions are observed for outside BNNT although with the Fe–Co alloy nanowires inside, but the outward relaxations of the N atoms bonding to the Fe or Co atoms are smaller due to their attractions. The combining processes of Fe–Co/BNNT composites are endothermic when Co concentration x≤0.6 and exothermic x>0.6, and the most stable Fe–Co/BNNT composite is at Co concentration x=0.8. So the semiconducting (10,0) BNNT can be used to shield the Co-rich Fe–Co nanowires. The charges are transferred from Fe–Co nanowires to BNNT and the formed Co–N bonds have covalent bond as well as slight ionic bond characters. Although (10,0) BNNT is nonmagnetic and a decrease in the magnetic moment is found after Fe–Co nanowires are encapsulated inside (10,0) BNNT, the Fe–Co/BNNT composites still have large magnetic moment, reflecting they can be utilized in magnetic storage and ultra high-density magnetic recording devices. 相似文献
11.
Temperature-dependent, in-plane, thermoelectric power data are presented for single crystals of Ba(Fe1?x Co x )2As2 (0?≤?x?≤?0.05) and Ba(Fe1?x Rh x )2As2 (0?≤?x?≤?0.171). Given that previous thermoelectric power and angle resolved photoemission spectroscopy studies of Ba(Fe1?x Co x )2As2 delineated a rather large Co-concentration range for Lifshitz transitions to occur, and the underdoped side of the phase diagram is poorly explored, new measurements of thermoelectric power on tightly spaced concentrations of Co, 0?≤?x?≤?0.05, were carried out. The data suggest evidence of a Lifshitz transition, but instead of a discontinuous jump in thermoelectric power in the range 0?≤?x?≤?0.05, a more gradual evolution in the S(T) plots as x is increased was observed. The thermoelectric power data of Ba(Fe1?x Rh x )2As2 show very similar behavior to that of Co substituted BaFe2As2. The previously outlined T–x phase diagrams for both systems are further confirmed by these thermoelectric power data. 相似文献
12.
B. Kalska-Szostko M. Hilgendorff M. Giersig P. Fumagalli 《Applied Physics A: Materials Science & Processing》2013,111(3):853-859
The magneto-optical properties of 14-nm Co x Ag1?x core–shell nanoparticles (x=0.7, 0.8, and 0.35) deposited on different substrates are investigated at room temperature in the photon-energy range from 0.8 to 4.8 eV. Particles with low Ag content show spectra very similar to pure Co nanoparticles while particles with high Ag content have totally different features, where the Ag plasma edge dominates the spectra. The spectral features of the polar Kerr rotation depend on particle composition. The ageing process and development of an oxide layer influence the particles’ core–shell structures and magnetization curves. Co-rich particles exhibit lower resistance to the oxidation process as compared to Ag-rich ones. The quality of the nanoparticles was checked by transmission electron microscopy in respect of time scale. 相似文献
13.
Yu. P. Smirnov A. E. Sovestnov V. A. Shaburov A. V. Tyunis 《Physics of the Solid State》1999,41(9):1399-1401
The electronic structure of Rh, Pt, In, and Sn in the mixed-valence systems Eu(Rh1−x
Ptx)2 and U(In1−x
Snx)3 has been studied by the x-ray K line-shift method. It has been found that the occupation of the Rh 4d-shell in Eu(Rh1−x
Ptx)2 is higher than that in the metal, and that it grows with decreasing Eu valence (i.e., with increasing 4f-shell occupation). The electronic structure of Pt, In, and Sn in Eu(Rh1−x
Ptx)2 and U(In1−x
Snx)3 does not depend on the Eu and U valence and is practically the same as in the metals. These features in the electronic structure
of Rh, Pt, In, and Sn in Eu(Rh1−x
Ptx)2 and U(In1−x
Snx)3 suggest that the electron released in the f
n
→ f
n
−1+e transitions, rather than transferring to the common conduction band, remains localized at the Eu and U atoms.
Fiz. Tverd. Tela (St. Petersburg) 41, 1529–1531 (September 1999) 相似文献
14.
Surprisingly, Np2Rh2Sn does not order magnetically whereas the uranium counterpart U2Rh2Sn orders antiferromagnetically at 24 K with a 5f moment μ
U
≈0.38μ
B
. We have investigated the magnetic and electronic properties of (U1−x
Np
x
)2Rh2Sn solid solutions. For x=0.25 and 0.5, the ordering temperature decreases to 11 K whereas the Np-rich compound (x=0.75) shows the onset of magnetic order around T≈6 K. The average Np magnetic moment amounts to 0.84 μ
B
,0.83μ
B
and 0.25 μ
B
respectively. The isomer shift slightly decreases, from −9.6 mm/s to −10.4 mm/s (versus NpAl2) as x increases. The values of the quadrupole interaction parameter in the ordered and paramagnetic state suggest that Np moments
are parallel to c for x=0.25 and then rotate to the basal plane for higher x.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
15.
L. Bottyán J. Dengler Gy. Faigel N. E. Kaner D. L. Nagy G. Ritter U. Röhlich 《Hyperfine Interactions》1994,93(1):1647-1651
YBa2(Cu1-x
57Fe
x
)3O7–y
powder samples withx=0.02 and 0.03 were uniaxiallyc-aligned in epoxy in a magnetic field of 7.5 T. An X-ray map of the distribution of the orientation of the crystallographicc-axes of the individual crystallites was determined.57Fe Mössbauer spectra were recorded at room temperature as a function of the angle between the texture axis and the observation direction. Different sets of EFG parameters were selected from the literature and the fit constraints were equally set for all. Using a model of the measured texture function and accounting for polarization-dependent blackness effects, a simultaneous fit of the Mössbauer spectra results in minimum
2 for the EFG set determined previously from CEMS data on this films.On leave from: Institute for Low Temperature Physics and Engineering, Ukr. Acad. Sci., Kharkov, Ukraine. 相似文献
16.
17.
T. I. Arbuzova I. B. Smolyak S. V. Naumov A. A. Samokhvalov A. V. Korolev 《Journal of Experimental and Theoretical Physics》2001,92(1):100-107
The magnetic properties of La1 ? x CaxMnO3 solid solutions were studied in wide temperature and magnetic field ranges, T = 2–600 K and H ≤ 50 kOe. Semiconducting compositions with 0.6 < × < 0.9 exhibited an unusual temperature behavior of magnetization and susceptibility with well-defined Curie and Néel temperatures. The simultaneous manifestation of both ferromagnetic and antiferromagnetic properties is evidence of the coexistence of two collinear magnetic phases. The content of impurity ions was shown to have a strong influence on the T C and T N values, whereas the ratio between the ferro-and antiferromagnetic phase volumes heavily depended on thermal treatment conditions. The magnetic properties of the whole series of La1 ? x CaxMnO3 solid solutions can be explained in terms of the phase separation model. 相似文献
18.
《Journal of Electron Spectroscopy and Related Phenomena》1987,44(1):163-174
High resolution electron energy loss Spectroscopy (HREELS), X-ray photoelectron Spectroscopy (XPS) and low energy electron diffraction (LEED) have been used to characterize initial stages of oxidation of Si(100)2x1 and Gex Si1−x (100)2x1 surfaces. Different oxidation stages of Si were identified by measuring Si 2p core level shifts and characteristic vibrations of Si-O-Si complexes. The latter may be described in the framework of continuous random network models.Then,from the experimentally determined frequencies, force constants,average bond angles and bond lengths are determined. Complementary,marker experiments with atomic hydrogen as a probe in conjunction with HREELS were used to determine the local, atomic structure for different stages of oxidation from chemical shifts of Si-H and Ge-H stretching mode intensities, respectively. 相似文献
19.
M. M. Abd-Elmeguid Ch. Sauer U. Köbler W. Zinn 《Zeitschrift für Physik B Condensed Matter》1985,60(2-4):239-248
X-ray diffraction,151Eu Mössbauer effect (ME) and magnetic susceptibility measurements have been performed to investigate the valence behavior and the magnetic interactions of the Eu ions in the intermetallic series Eu(Pd1–x
Au
x
)2Si2 (0x1) as a Forx>0.4 all experimental techniques are in agreement with each other and suggest a divalent 4f
7 ground state of the Eu ion. Belowx=0.4 the different methods lead to different results: while the lattice parameters and the ME isomer shift suggest an instable behavior of the valence the magnetic susceptibility proves a pure divalent 4f
7 ground state. These differences can be explained by assuming a partial extension of the 4f-shell radius such that the localized character of the 4f-electrons is preserved.Dedicated to B. Mühlschlegel on the occasion of his 60th birthday 相似文献
20.