Evidence of non-statistical structures in the elastic and inelastic scattering of58Ni+58Ni and58Ni+62Ni and intermediate dinuclear states

Excitation functions and angular distributions of⁵⁸Ni+⁵⁸Ni and⁵⁸Ni+⁶²Ni scattering at energies just above the Coulomb barrier have been measured aroundθ _cm=90° in energy stepsΔE _cm=0.25 MeV fromE _cm ? 110 MeV toE _cm ? 120 MeV for⁵⁸Ni+⁵⁸Ni and fromE _cm ? 110 MeV toE _cm ? 118 MeV for⁵⁸Ni+⁶²Ni. Evidence for structure of non-statistical character has been found in the angle-summed excitation functions; this evidence is corroborated by the analysis of the angular distributions. This is the first time that non-statistical structure in elastic and inelastic scattering is reported with high confidence level for this mass and excitation energy ranges. Attempts are presented to understand the nature of this structure, including the presence of intermediate dinuclear states and virtual states in a potential well.     

Clustering states in the62Ni(58Ni,58Ni)62Ni reaction

Excitation function and angular distributions of the⁶²Ni(⁵⁸Ni,⁵⁸Ni)⁶²Ni elastic scattering have been measured at incident⁵⁸Ni energies from 220.0 to 230.0 MeV in steps of 0.5 MeV. Evidence of two structures was found in the excitation function; a statistical analysis suggests a possible nuclear cluster quasi-molecular nature for these structures.     

AB initio calculation of tight-binding parameters of the NiNi,NiH,NiO,NiS bonds

Calculations of the tight-binding parameters of the NiNi, NiH, NiO and NiS bonds have been carried out using wavefunctions and effective potentials obtained from an atomic self consistent Hartree - Fock - Slater calculation. Results for the NiNi bond agree with the available parameters obtained through interpolation schemes. A study has also been made, of the variations of parameters with bond length and the parameters are shown to decrease rapidly with increasing distance.     

Electronic structure of the ordered ferromagnetic alloys Ni3Mn,Ni3Fe,and Ni3Co

Calculations of the band structure of the ferromagnetic alloys Ni₃Mn, Ni₃Fe, and Ni₃Co are presented. The results are compared with experimental data. Change in the electronic structure as one goes from Ni₃Mn to Ni₃Co is analyzed. The occurrence of ferromagnetism in the alloys studied and the possibility of their existence in an ordered ferromagnetic state are examined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 82–88, June, 1988.     

Elastic scattering of Ni+Ni near the Coulomb barrier

Elastic scattering angular distributions have been measured for ⁵⁸Ni+⁶⁴Ni at three energies around the Coulomb barrier employing a new kinematic coincidence technique. The data are compared with the results of coupled-channels calculations including inelastic excitations as well as one-and two-neutron transfer reactions. The agreement is good and the calculations also agree well with the available transfer and fusion reaction data.     

耐蚀合金Al3Ni和Ni3Al液态冷凝过程的比较研究

采用F S多体势对液态合金Al3Ni和Ni3Al在不同冷却速度下的微观结构及其转变机制进行了分子动力学模拟 ,得到了不同冷速下各温度的双体分布函数 ;采用HA键型指数法对其结构进行了分析 ,结果表明 :Al3Ni在两种冷速下均以非晶的形式出现 ,只是慢冷时体系的有序度略有升高 ;而Ni3Al的结构及能量转变受冷速影响较大 ,快冷时形成非晶 ,而慢冷时出现明显结晶 ;同样冷速下Al含量较少的Ni3Al体系的有序度高 ,更易形成晶体 ,晶体的形成过程中有能量突变 .     

X-ray photoelectron spectroscopy of Ni in Ni–Zn and Ni–Al alloys

X-ray photoelectron spectroscopy measurements on Ni in the alloys Ni, Ni₅₀Zn₅₀, Ni₂₀Zn₈₀ and Ni₅₀Al₅₀ have been made and confirm previous measurements of the band structure. The satellite lines on the Ni 2p and 3s lines are found to be present in the spectra even when the density of 3d states at the Fermi energy is low.     

Studies in the vibrational splitting of the giant dipole resonance (II). Ni and Ni

The total photoneutron cross sections for ⁵⁸Ni and ⁶⁰Ni have been measured with bremsstrahlung from threshold to 24 MeV. Although their magnitudes are greatly different, the two cross sections show similar structure over the giant dipole resonance region. The structural features of both are in only fair agreement with the dynamic collective model calculations of Huber, and of Seaborn, Drechsel, Arenhövel and Greiner. However the agreement of the ⁶⁰Ni cross section and the collective correlations calculation of Seaborn et al. is far better, and thus indicates the importance of shell-model aspects.     

成分和厚度的依赖

通过调整Mn的成分，系统地研究了Ni81Fe19/Ni100-xMnx双层膜的磁学性质，特别是交换偏置场(Hex)的变化.当Ni100-xMnx中Mn的原子百分比在534%到600%之间时，对于150nm的Ni81Fe19，得到了最大的交换偏置场175kA/m，同时由于Mn对Ni81Fe19层的扩散所造成的磁矩的降低小于20%；高角x射线衍射证明Ni100-xMnx的晶格常数随着Mn成分的改变而变化，Mn含量越多，其晶格常数越大；制备态Ni100-xMnx膜晶格常数与θ相NiMn膜晶格常数的接近程度与NiMn膜θ相形成的容易程度相对应.也研究了交换偏置场随着Ni１００-xMnx厚度的变化，第一次得到了当Ni100-xMnx中Mn的原子百分比为706%时，Ni81Fe19(150nm)/Ni100-xMnx(90nm)双层膜在经过240℃，5h退火后，可以有80kA/m的交换偏置场，此时铁磁层磁矩的大小几乎不变. 关键词： Ni81Fe19/Ni100-xMnx 交换偏置场     

Molecular Dynamics Simulation of the Migration of Tilt Grain Boundaries in Ni and Ni3Al

Journal of Experimental and Theoretical Physics - The migration of the 〈100〉 and 〈111〉 tilt boundaries in Ni and the Ni3Al intermetallic compound is studied by molecular...     

Damped oscillations in the energy autocorrelation functions of the 58Ni+46Ti elastic and 58Ni+62Ni elastic and inelastic scattering cross sections

Structures of non-statistical character, recently observed in ⁵⁸ Ni +⁴⁶ Ti elastic and ⁵⁸ Ni +⁶² Ni elastic and inelastic excitation functions, produce damped oscillations in the cross section energy autocorrelation functions. The analysis of these damped oscillations in terms of S-matrix spin and parity decoherence indicates, as a possible interpretation, damping of the coherent rotational motion of the intermediate dinuclear system formed in the reaction.     

An EPR study of Ni+ centers in SrF2:Ni and BaF2:Ni

An EPR study of RT X-irradiated SrF2:Ni and BaF2:Ni has been performed. Different kinds of Ni⁺ centers showing small deviations with respect to a basic structure have been observed. This basic structure consists of a Ni⁺ ion displaced along a <100> direction from the cation substitutional position toward the center of a face of the cube of fluorines. These results are similar to those previously reported on CaF2:Ni.

The spin Hamiltonian parameters of the different centers obtained from the analysis of the corresponding rotational diagrams are also reported.     

Calculation of the structure of the 4s band for Ni3Mn and Ni3Fe ordered alloys

Perturbation theory has been applied to the structure of the 4s band of Ni₃Mn and Ni₃Fe ordered alloys; the Fermi surfaces have been constructed for these alloys in the one-wave approximation, and the electron state densities and electron energy change on ordering have been calculated. It is found that the contribution of the 4s electrons to the ordering energy is much less than that of the 3d electrons.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 102–106, July, 1972.     

Theoretical study of the environmental effects on the hyperfine fields of Ni and Fe in Ni0.75Fe0.25

The dependence of the hyperfine fields B_hf of Ni and Fe in Ni_0.75Fe_0.25 on the surrounding atomic configuration has been studied by performing charge selfconsistent 6 shell-cluster Korringa-Kohn-Rostoker Coherent Potential Approximation (KKR-CPA) bandstructure calculations. By replacing the CPA- scatterers in the various shells around the central atom by Ni - or Fe-atoms, respectively, it could be shown that the hyperfine fields vary linearly with the number of Fe-atoms within a given shell and that the changes of B_hf due to simultaneous changes of the atomic configurations of different shells are additive. The changes of the hyperfine fields upon ordering of Ni_0.75Fe_0.25 solid solution as deduced from our calculations agrees reasonably well with experiments.     

Core hole satellites in Ni and Au Ni

The 2p core hole satellite structure in Ni and 5% Ni in Au are compared and discussed in terms of recent theoretical models. The large differences found for these two materials are explained in terms of the large differences in the Ni 3d band, and virtual bound state widths. The satellite structure for Au Ni is found to agree with the multiplet splitting of the free atom in a 2p⁵3d⁹ configuration.     

Characterisation of Ni and Ni/Ti contact on n-type 4H-SiC

In this work, we report on the structural characterisation of Ni and Ni/Ti bilayer contacts on n-type 4H-SiC. The redistribution of carbon, after annealing, in the Ni/SiC and the Ni/Ti/SiC contacts is particularly studied by RBS at 3.2 MeV, XRD and AES techniques.     

Thermal neutron captureγ-ray spectroscopy of59Ni and61Ni

Theγ-radiation emitted after thermal neutron capture in isotopically enriched⁵⁸Ni and⁶⁰Ni was measured at the ILL high flux reactor by means of Ge/NaI detectors operated in Compton suppression and pair spectrometer mode. The neutron binding energies were determined asB _n (⁵⁹Ni)=8999.15(23) keV and B_n(⁶¹Ni)=7820.07(20) keV; some 95% of the totalγ-ray fluxes through^59,61Ni were assigned. Theγ-ray strength functions of the primary transitions and the level densities are discussed.