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1.
Toshikazu Nakamura Tomoko Nobutoki Masao Miyamoto Yuichi Tsubokura Ryota Tsuchiya Toshihiro Takahashi Kazushi Kanoda Gunzi Saito 《Journal of Superconductivity and Novel Magnetism》1994,7(3):671-674
The electronic structure of the title superconductors has been investigated by electrical resistivity, complex susceptibility, and electron paramagnetic resonance (EPR) measurements. The superconducting properties (pressure dependence ofT c , magnetic penetration depth, upper critical field, and so on) of these three salts are similar to each other, while transport properties in the normal state have shown a large variety in the temperature dependence. In order to clarify the electronic structure in the normal state, the EPR parameters, the spin susceptibility (χ spin), and the linewidth (ΔH pp), are compared. An anomalous temperature dependence of theg-value has been observed below 150 K in the Cu(NCS)2 and Cu(CN)[N(CN)2] salts. 相似文献
2.
The magnetic susceptibility of Al-Co-Ce and Al-Co-Dy amorphous alloys is investigated in a wide range of temperatures (t = 20?1700 °C) and magnetic fields (B = 0.3?1.3 T). A weak gC(B) dependence in the entire temperature range and an anomalous increase in susceptibility beginning above the melting temperature of Al2R compound are revealed for all investigated compositions. The experimental data are used to calculate the parameters of the electronic structure of alloys and to estimate the size of super-paramagnetic inclusions. It follows from the experimental data that cobalt atoms are present in these alloys in the nonmagnetic state. It is found that the values of effective magnetic moments on cerium and dysprosium atoms are significantly lower than those for R3+ ions and independent of the chemical composition of alloys. The results are discussed assuming the existence in melts of microregions formed by quasi-molecules of Al2R. 相似文献
3.
Hiroshi Nozaki 《Materials Research Bulletin》1981,16(7):861-868
The system of V1?xTixS1.40 has been studied through magnetic susceptibility and NMR measurements. The Curie constant increases with quadratic dependence on the composition x within the V3S4 phase (0 ≤ x ≤ 0.6) and then, rapidly decreases toward the Ti2S3 phase (0.8 < x ≤ 1.0). The NMR absorption from V51 nuclei with itinerant delectrons rapidly decreases with increasing Ti content in the former phase. These phenomena may indicate that local magnetic moments are formed in this system under a particular environment of vanadium atoms proposed. Metal distribution of V and Ti is also discussed. 相似文献
4.
5.
The role of the Ce sublattices in the thermal and magnetic properties of the Ce7
X
3 (X=Ni, Ru, Rh, Ir, Pd, and Pt) family of compounds is studied by means of ac and dc magnetic susceptibility, magnetization and
mainly specific-heat experiments in applied magnetic field. The experimental data show that in these compounds there is coexistence
of magnetic order, heavyfermion and intermediate-valence behavior, which is interpreted in terms of the contribution of the
three different sublattices present in the crystalline structure of Th7Fe3-type (denoted by 1CeI, 3CeII, and 3CeIII). From the available volume of the CeIII atoms in their crystallographic environment it is found that sublattice CeIII has an intermediate-valence behavior, whereas from entropic considerations sublattices CeI and CeII are identified as responsible for the magnetic order or heavy-fermion behavior, depending on the Ce-ligand electronic structure.
This systematics evidences a clear correlation between the thermal and magnetic properties of these compounds and the position
of the respective Ce-ligands in the periodic table, through the particular sensitivity of Ce to the environmental conditions. 相似文献
6.
Magnetic susceptibility, resistivity, specific heat, and thermoelectric power measurements on EuCu2Si2, YbCu2Si2, CeCu2Si2, and GdCu2Si2 are presented. The first three compounds show a demagnetization of the 4f shell, while the fourth was studied to determine the normal magnetic and electronic properties for the RE-Cu2Si2 system. YbCu2Si2, CeCu2Si2, and EuCu2Si2 are found to exhibit similar lattice, electronic, and magnetic properties: an intermediate lattice constant; a magnetic susceptibility that is large and paramagnetic but neither shows order nor a Curie divergence; a large electronic specific heat coefficient; strong deviations from a simple T law in the high-temperature resistivity; and a large maximum in the thermoelectric power. The data are interpreted in terms of interconfiguration fluctuations (ICF), and a simple model is presented which can quantitatively explain the magnetic susceptibility and semiquantitatively predicts the specific heat. In addition, the model is in qualitative agreement with the resistivity and thermoelectric power data.Supported by Air Force Grant No. AF-AFOSR-71-2073 and by U.S. Atomic Energy Commission Contract No. USAEC-AT-(04-3)-34. 相似文献
7.
R. Masrour A. Jabar E. K. Hlil M. Hamedoun A. Benyoussef H. El Moussaoui O. Mounkachi A. Hourmatallah A. Rezzouk A. Marzouk K. Bouslykhane N. Benzakour 《Journal of Superconductivity and Novel Magnetism》2016,29(8):2059-2063
The self-consistent abinitio calculations, based on DFT (density functional theory) approach and using FLAPW (full-potential linear augmented plane wave) method, are performed to investigate both electronic and magnetic properties of the FeBr 2 compound. Polarized spin and spin-orbit coupling are included in calculations within the framework of the ferromagnetic state between two adjacent Fe atoms. Magnetic moments considered to lie along (001) axes are computed. The antiferromagnetic and ferromagnetic energies of FeBr 2 are estimated. Obtained data from abinitio calculations are used as input for the high-temperature series expansion (HTSE) calculations to compute other magnetic parameters. The exchange interactions between the magnetic atoms Fe–Fe in FeBr 2 are established by using the mean field theory. The critical temperature T C(K) is obtained by HTSEs combined with the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is established. The critical temperature and magnetic hysteresis cycle are obtained by Monte Carlo simulation. 相似文献
8.
《Computational Materials Science》2011,50(2):737-741
We have investigated the structural, electronic, and magnetic properties of a newly discovered antiperovskite superconductor ZnNNi3 and related compounds ZnCNi3 and ZnNi3 by using full-potential linearized augmented plane-wave method with the generalized gradient approximation (GGA). It is found that the electronic structures of ZnNNi3 and ZnCNi3 are very similar, existing a characteristic density of states (DOS) peak just below the Fermi level, which is dominated by Ni d bands with a small contribution from N/C p states. Contrarily, the band structure and Fermi surface in ZnNi3 is changed considerably. Based on the free electron model, the Sommerfeld coefficients and the molar Pauli paramagnetic susceptibility for these compounds are evaluated. The spin-polarized calculations and the fixed spin-moment calculations indicate that both ZnNNi3 and ZnCNi3 are not near magnetism, while ZnNi3 shows a typically ferromagnetic behavior. Furthermore, we also investigated the influence of N/C-defect on the electronic and magnetic properties. We found that ZnCNi3 is more sensitive to the defect than ZnNNi3, which well explains the fact why superconductivity has not yet been observed in ZnCNi3. 相似文献
9.
Fatemeh Amiri Saeed Mahdavifar Hanif Hadipour 《Journal of Superconductivity and Novel Magnetism》2014,27(10):2379-2383
We have studied the magnetization process in the spin S = 1/2 antiferromagnetic two-leg ladder compound (C5H12N)2 CuBr4 by using the analytical fermionization technique. The magnetization and the susceptibility are calculated as functions of the temperature and the external magnetic field. The magnetization of the system shows various behaviors in different regions of the magnetic field. The field-dependence of the susceptibility is almost symmetric about the average of quantum critical fields in the low-temperature region leading to a complete agreement with the experimental results. 相似文献
10.
R. Masrour E. K. Hlil M. Hamedoun A. Benyoussef O. Mounkachi H. El Moussaoui 《Journal of Superconductivity and Novel Magnetism》2014,27(12):2747-2750
The self-consistent ab initio calculations, based on density functional theory (DFT) approach and using full-potential linear augmented plane wave (FLAPW) method, are performed to investigate both electronic and magnetic properties of the MnAs compounds. Polarized spin and spin-orbit coupling are included in calculations within the framework of the ferromagnetic state between two adjacent Mn atoms. The ferromagnetic and antiferromagnetic energies of MnAs systems are obtained. Magnetic moment considered to lie along (001) axes is computed. The obtained data from ab initio calculations are used as input for the high-temperature series expansion (HTSE) calculations to compute other magnetic parameters. The exchange interactions between the magnetic atoms Mn-Mn in MnAs are given using the mean field theory. The HTSEs of the magnetic susceptibility with the magnetic moments in MnAs (m Mn) through the Ising model is given up to the tenth order series in x=J 1(Mn-Mn)/ k B T. The Néel temperature T C is obtained by HTSEs of the magnetic susceptibility series combined with the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is deduced as well. 相似文献
11.
We present ab initio density functional calculations of the electronic structure and magnetic properties of X2/Cr36(001) and X1/Cr37(001) multilayers, with X = Sn, V and Mn, to investigate the impact of the proximity effects of the X layers on the spin density waves of the Cr slab. We find different magnetic profiles corresponding to the spin density wave and to the layered antiferromagnetic configurations. The nature of the different magnetic solutions is discussed in terms of the different interfacial environments in the proximity of Sn, V or Mn. The magnetic behavior at the interface is discussed in connection with the electronic structure through the density of electronic states projected at the interfacial X and Cr sites. We compare the results with those previously obtained for Fe3/X1/Cr37/X1(001) multilayers to analyze the role played by the ferromagnetic iron slab. 相似文献
12.
J. C. Parlebas 《Journal of Low Temperature Physics》1975,19(3-4):317-339
Using a realistic band structure for the host (noble or transition metal), we present a detailed study of the electronic and magnetic properties of transitional impurity clusters without interactions between the clusters. For the calculation of the one-electron properties, the Hartree-Fock environment effects are self-consistently taken into account by Friedel's rule. The impurity potentials and densities of states are very sensitive to the impurity-impurity interactions inside the clusters. For the calculation of the magnetic properties, the electron-electron interactions are taken into account in the random phase approximation, which allows one to obtain simple expressions for the specific heat and the low-temperature-dependent resistivity. These properties are expressed in terms of three characteristic temperatures T
f(1), T
f(2)
+
, and T
f(2)
–
corresponding to three different modes of spin fluctuations for the considered model. We present numerical results from the study of the local magnetic susceptibility, which depends on local environments via several combined effects. Our conclusions on nearly magnetic copper-based alloys are in good agreement with the experimental data. In particular, our calculations confirm that a magnetic moment appears on a nickel atom when it is surrounded by approximately eight nearest-neighboring Ni atoms.This publication is a part of a thesis to be presented at the University Louis Pasteur. 相似文献
13.
We have studied the magnetic, electrical, and optical properties of (HgS)1.5(Al2S3)0.5〈Mn〉 and (HgS)1.5(In2S3)0.5〈Mn〉 crystals and determined their magnetic and band structure parameters. The magnetic (Faraday method) and transport (four-probe method) properties of the (HgS)1.5(Al2S3)0.5〈Mn〉 and (HgS)1.5(In2S3)0.5〈Mn〉 crystals were investigated in the ranges T = 77−300 K and H = 20−320 kA/m. The magnetic susceptibility data suggest that the magnetic properties of the crystals can be understood in terms of Mn-S-Mn-S clusters. The Hall coefficient of the crystals is temperature-independent. The electrical conductivity of (HgS)1.5(Al2S3)0.5〈Mn〉 varies little with temperature and has a maximum, and that of (HgS)1.5(In2S3)0.5〈Mn〉 shows metallic behavior and is a nearly linear function of temperature. The thermopower of the crystals increases with temperature. Optical data attest to direct allowed interband optical transitions. The magnetic and band structure parameters of the crystals are determined. 相似文献
14.
N. Guskos S. Glenis K. Karkas G. Zolnierkiewicz M. Bosacka 《Materials Science-Poland》2013,31(1):25-28
The electronic properties of multicomponent vanadate oxides M2InV3O11 (M(II) = Zn(II) and Co(II)) were investigated by electrical resistivity and electron paramagnetic resonance (EPR) measurements. Replacement of non-magnetic Zn(II) cations with magnetic Co(II) ions resulted in a significant drop in the electrical conductivity and an increase in the activation energy. The EPR spectroscopy revealed the presence of VO2+ vanadyl ions in both compounds, while the presence of divalent cobalt ions was identified in the Co2InV3O11 oxide at low temperatures. The concentration of VO2+ vanadyl ions was found to be about one order higher for the vanadate oxide without magnetic ions. It is suggested that the increased concentration of VO2+ ions could be responsible for the enhanced conductivity of Zn2InV3O11. 相似文献
15.
R. Masrour E. K. Hlil M. Hamedoun A. Benyoussef O. Mounkachi H. El Moussaoui 《Journal of Superconductivity and Novel Magnetism》2015,28(6):1815-1819
The self-consistent ab initio calculations, based on density functional theory (DFT) approach and using full-potential linear augmented plane wave (FLAPW) method, are performed to investigate both electronic and magnetic properties of the MnSb compounds. Polarized spin and spin-orbit coupling are included in calculations within the framework of the ferromagnetic state between two adjacent Mn atoms. The ferromagnetic energy of MnSb systems is obtained. Magnetic moment considered to lie along the (001) axes are computed. The exchange interactions between the magnetic atoms Mn–Mn in MnSb are given using the mean field theory. Obtained data from ab initio calculations are used as input for the high-temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The HTSEs of the magnetic susceptibility of the magnetic moments in MnSb (m Mn) is given up to the tenth order series in (x = J 1(Mn–Mn)/ k B T). The critical temperature T C is deduced by HTSEs of the magnetic susceptibility series combined with the Padé approximation method. The critical exponent γ associated with the magnetic susceptibility is deduced as well. 相似文献
16.
I. Felner M. I. Tsindlekht G. Gorodetsky E. Rosenberg 《Journal of Superconductivity and Novel Magnetism》2000,13(4):659-661
Detailed magnetic and nonlinear susceptibility measurements of the La1?x Zn x MnO3 system are reported. For x = 0.05 and 0.1, a typical ferromagnetic (FM) signal in the field-cooled curve is observed at 38 K. However, for the insulating antiferromagnetic (AFM) parent compound LaMnO3 and for the x = 0.2 and 0.33 samples, the magnetization curves in the low temperature range, are smooth and flat. This observation confirms the coexistence of finite FM clusters in the insulating AFM region below the critical concentration (x c = 0.16) for percolation, predicted by the percolation model. 相似文献
17.
K. N. Yang M. S. Torikachvili M. B. Maple H. C. Ku 《Journal of Low Temperature Physics》1984,56(5-6):601-616
Low-temperature specific heat, electrical resistivity, ac magnetic susceptibility, and dc magnetization measurements were made on ternary cerium and uranium transition metal borides with the general formula CeT3B2 (T=Co, Ru, Rh, and Ir) and UT3B2 (T=Co, Ru, and Ir). The compound CeRu3B2 was found to exhibit superconductivity below 0.68 K. The values of the electronic specific heat coefficient range from 9.7 mJ/mole-K2 for CeCo3B2 to 64 mJ/mole-K2 for UIr3B2. The electrical resistivity versus temperature curves of all of the compounds exhibit negative curvature and are reminiscent of valence fluctuation behavior. In the case of CeIr3B2, the electrical resistivity attains a maximum value at 180 K, while the dc magnetic susceptibility has a temperature dependence that is typical of intermediate valence Ce compounds, approaching a finite value at zero temperature. The electrical resistivity of the ferromagnetic compound CeRh3B2 reveals a rapid decrease in spin disorder resistivity below 120 K. The dc magnetic susceptibility of this material can be described as the sum of a constant term and a Curie-Weiss contribution with an effective magnetic moment of 1.01 µB per formula unit and a Curie-Weiss temperature of 119 K. Magnetization measurements on CeRh3B2 yield a saturation magnetic moment of 0.37 µB per formula unit and a Curie temperature of 113 K. 相似文献
18.
The intensity of magnetization and the isentropic magnetic susceptibility of Mn(NH4)2(SO4)2 · 6H2O have been determined along 13 isentropes (between 0.620 and 2.825 cal mole–1 deg–1) in fields up to 1670 Oe directed along theb-axis of a spherical single crystal. Eleven of the isentropes originated, in zero field, within the Curie region of the salt. Field increments of 10 to 15 Oe were used below 170 Oe, with larger steps above this. All isentropes originating within the Curie region show a common (high) susceptibility at zero field. In each case the susceptibility then drops sharply at a small field characteristic of the particular entropy. The drop in susceptibility was used to define the boundaries of the Curie region (critical fieldvs entropy). The change of temperature with magnetic field was determined along the isentropes and examples are given. 相似文献
19.
R. Masrour E. K. Hlil M. Hamedoun A. Benyoussef O. Mounkachi L. Bahmad 《Journal of Superconductivity and Novel Magnetism》2013,26(11):3325-3329
Self-consistent ab initio calculations, based on DFT (Density Functional Theory) approach and using the FLAPW (Full potential Linear Augmented Plane Wave) method, are performed to investigate both electronic and magnetic properties of the MnO layers. Polarized spin and spin-orbit coupling are included in calculations within the framework of the antiferromagnetic state between two adjacent Mn layers. Magnetic moment considered to lie along (110) axes are computed. Obtained data from ab initio calculations are used as input for the high temperature series expansions (HTSEs) calculations to compute other magnetic parameters. The exchange integrals between the magnetic atoms Mn–Mn and Mn–O in the same layer and between the adjacent bilayers are given by using the mean field theory. The antiferromagnetic energies of MnO layers are obtained. The High Temperature Series Expansions (HTSEs) of the magnetic susceptibility on MnO antiferromagnetic layers through Heisenberg and XY models is given up to tenth order series in (x=J Mn–Mn/k B T). The reduced Néel temperature x N is obtained by HTSEs of the magnetic susceptibility and by using the Padé approximant method. The critical exponent γ associated with the magnetic susceptibility is deduced. 相似文献
20.
Kiran Singh Wilfried Hermes Som Datta Kaushik Sarkarainadar Balamurugan Shovit Bhattacharya Neeraj Kumar Gaur Sudhindra Rayaprol Rainer Pöttgen 《Journal of Superconductivity and Novel Magnetism》2009,22(8):759-767
A series of compounds R
2CaBa2Cu5O
z
(R=La, Pr, Nd and Eu) have been synthesized by conventional solid state reaction and characterized for their structural, superconducting
and magnetic properties. All compounds crystallize with the tetragonal LaBa2Cu3O
z
type structure, space group P4/mmm. Among the four compounds studied here, R=La, Nd and Eu are superconductors with superconducting transition temperatures (T
c
R=0) of 72, 40 and 55 K, respectively. On the other hand, neither superconductivity nor magnetic ordering is seen for R=Pr down to 3 K. The effect of the magnetic field on the susceptibility and (magneto) resistance for the superconducting samples
has been investigated. The superconductivity of compounds with magnetic rare-earth ions Nd and Eu exhibit a profound influence
of the magnetic field, whereas the application of the magnetic field has a limited effect on the La compound. The Pr compound
is paramagnetic and does not exhibit magnetic ordering either. 相似文献