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.     

Influence of doping with titanium on the electronic structure of Ni3Fe and Ni3Mn in ordering

The specific electrical resistance , mean magnetic moment of an atom of the alloy, and the anomalous Hall (R_s) and Nernst-Ettinghausen (Q_s) constants of ordered alloys Ni₃(Fe, Ti) and Ni₃(Mn, Ti) are investigated. It is suggested that there is an additional degree of delocalization of the 3d electrons of the system Ni₃(Mn, Ti) and increase in the degree of localization of 3d electrons of the system Ni₃(Fe, Ti) with small additions of Ti, with increase in the long-range-order parameter. A model of the electronic structure of the given alloys is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 56–59, October, 1981.     

Ordering processes and activation energy in Ni3Fe-based ternary alloys

The measurement of electrical resistance () has been used, to study the kinetics of isothermal ordering in the range 200 °–545 ° C in Ni₃(FeMn) alloy quenched from 970 ° C, and the kinetics of ordering at 390 ° C in the alloy quenched from various temperatures in the 600 °–800 ° C range. The sections method and the gradient of the (t) curves were used to find the activation energy for migration and vacancy formation in this alloy on the assumption that the excess vacancies frozen in the alloy by quenching at temperatures above T_c are responsible for ordering. The activation energies for vacancy formation and migration were respectively U₀ = 33 ± 3 kilocal/mole and U_m = 39 ± 4 kilocal/mole, which in total give the activation energy for diffusion Q = 72 ± 7 kilocal/mole in the alloy studied; this approximates to the activation energy for diffusion in pure nickel.     

Change in strain hardening and elastic properties during isothermal ordering of alloys based on Ni3Fe

A study has been made of the change in the Young's modulus, yield point, hardness, hardening coefficient, slip pattern, and duration of the linear stage in the flow curves during the isothermal ordering of the polycrystalline alloys Ni₃Fe, Ni₃(Fe + 2% Al), Ni₃(Fe + 3% Mn), and Ni₃(Fe + 2.5% Cr). A definite relationship has been observed between the changes in these properties at the various stages of ordering.     

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.     

Hall effect in the ternary ordered alloys Ni3(Mn,Fe) and Ni3(Mn,Co) 1. Disordered solution solutions

The normal and anomalous Hall constants R₀ and R_s, respectively, and the resistivity have been measured for the quasibinary alloys Ni₃Mn-Ni₃Fe and Ni₃Mn-Ni₃Co. The results imply that in ternary alloys of Ni₃Mn containing slight Fe and Co impurities the hole regions of the Fermi surface make an important contribution to R₀ and that the primary scattering mechanism for the carriers corresponding to the anomalous Hall current in the alloys with Fe at room temperature is phonon scattering. It is concluded that the Fermi surface of the Ni₃Mn-Ni₃Fe alloys is closed.Translated from Izvestiya VUZ. Fizika, No. 3, pp. 21–29, March, 1970.     

Hall effect in the ternary ordered alloys Ni3(Mn,Fe) and Ni3(Mn,Co) II. Ordered solid solutions

An experimental study was made of the changes in the normal and anomalous Hall constants R₀ and R_s, respectively, the internal saturation induction B_s, and the resistivity ? during the ordering of quasibinary Ni₃Mn-Ni₃Fe and Ni₃Mn-Ni₃Co alloys. The concentration dependences of R₀, R_s, B_s, and ? were also studied in the ordered state of these alloys. It is concluded from an analysis of the experimental results that the decreases inR₀ and ? during the ordering of Ni₃Mn and as a result of the alloying of ordered Ni₃Mn with slight amounts (～5 at. %) of iron are due primarily to a decrease in the hole contribution to transport and to a decrease in the state density in the 3d band of these alloys near the Fermi level. The experimental data are in satisfactory agreement with the curve calculated by Yamashita et al. [6] for the density of 3d states in ordered Ni₃Mn and Ni₃Fe alloys.     

Certain features of the electronic structure of ternary alloys of Ni3Mn with iron and cobalt

Features of the electronic structure of ternary alloys of the quasibinary Ni₃Mn-Ni₃Fe and Ni₃Mn-Ni₃Co systems are discussed on the basis of an analysis of the changes in the absolute thermal emf S and in the conductivity . It is concluded that all the ternary Ni₃Mn-Ni₃Fe alloys have a closed Fermi surface in both the disordered and ordered states. It is confirmed experimentally that a deep minimum appears on the state-density curve N_d(E) during the ordering of Ni₃Mn-Ni₃Fe alloys, and the alloy composition whose Fermi surface corresponds to this minimum is given.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 8, pp. 126–133, August, 1969.     

Deformation hardening and temperature dependence of mechanical properties in ternary ordered alloys based on Ni3Fe I

The variation of hardening factor and resistance to deformation with the quenching and testing temperatures for ordered alloys based on Ni₃Fe was investigated. It was shown that the yield point _0.2 and flow stresses are independent of the quenching temperature right up to about 450 ° C. At higher quenching temperatures there are increases in _0.2 and in the flow stresses corresponding to small degrees of deformation ( < 10%); the highest mechanical properties are found when the quenching temperature is near the Curie point. In quenching from a temperature above the Curie point the mechanical properties and hardening factor fall suddenly to values corresponding to the disordered state of the alloys. The temperature variation of _0.2 is similar to that mentioned above. The deformation stress at high values and the hardening factor decrease with increase in testing temperature, and below the Curie point they reach values corresponding to the disordered state. The temperature variation of mechanical properties for specimens in which the formation of long-range order is suppressed by special treatment is characterized by the absence of substantial change near the Curie point. The results obtained are discussed in relation to modern dislocation theories of hardening of alloys with long-range order.     

Influence of low doses of gamma radiation on the ordering of Ni3Fe alloys

The results of electrical resistivity measurements taken over the course of time on the ordering of Ni₃Fe alloys after low-dose gamma irradiation are presented. A long-term, weak, aperiodic oscillation in the electrical resistivity of samples subjected to irradiation, and the absence of such oscillations in control samples was established. A change in the small-angle x-ray scattering after gamma ray irradiation of Ni₃Fe was observed.Tomsk Architectural and Civil Engineering Academy. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 89–92, September, 1993.     

Effect of a chromium admixture on the electronic structure and ordering of Ni3Mn

The effects of a chromium admixture on certain properties of the electronic structure and on the ordering of Ni₃Mn have been studied by neutron diffraction and by measurement of the resistivity , the internal saturation induction B_S, and the absolute thermal emf S. Analysis of the experimental data implies a closed Fermi surface for the Ni₃(Mn, Cr) alloys with a low chromium concentration c but an open Fermi surface for high c.Translated from Izvestiya VUZ. Fizika, No. 2, pp. 44–51, February, 1970.     

The nature of distribution of atoms,and its connection with electron structure in a number of ternary alloys on Ni3Mn basis

The influence of alloying the Ni₃Mn alloy with titanium, vanadium, or copper, on the superstructure of the alloy, was studied by the neutron diffraction method. It was shown that Ti, V, and Al stabilize the superstructure of Ni₃Mn, and Cu actively destroys it. The distribution of atoms of the alloying elements along the sites of fcc lattice and its connection with the electron structure of the alloy was analyzed. The different influence of alloying with a third element on the superstructure in alloys Ni₃Mn and Ni₃Fe is explained.     

Atomic ordering in ternary alloys with hcp structure of DO19 type

Atomic ordering is investigated in ternary substitution alloys with hexagonalclose-packed (hcp) structure of DO₁₉(Ti₃Al) type. The singularities are studied of the influence of the impurity of the third component C on the Kurnakov temperature and the degree of long-range order in the host atom arrangement. Phase diagrams are constructed for the ternary alloys with different values of the energy parameters and small concentrations of the component C. Changes in the phase diagram are analyzed for the binary alloy A-B upon addition of atoms C. Formulas are obtained to determine the energetic parameters of ternary alloys having a small concentration of one of the components. Computed as an illustration is a section of the phase diagram of the system Ti-Al-Fe and the iron atom distribution is studied over sites of the alloy crystalline lattice.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 70–77, March, 1987.     

Impurities in Ni3Fe magnetic alloys

The theoretical—in terms of the classical theory of ordering—and the experimental—with neutron diffraction analysis—investigations of the influence of the third component impurities on structural and magnetic ordering of Ni₃ Fe alloys have been carried out. Comparison of theoretical results with the experimental data, revealing the effect of the third component impurities of W, Mo, Cr and Mn atoms on the degree of atomic ordering and magnetization in Ni₃ Fe binary alloys, on order-disorder and Curie temperatures, and on the interrelation between atomic and magnetic ordering phenomena, shows good qualitative agreement between theory and experiments for all the systems chosen.     

Electronic structure of amorphous transition metal alloys

The electrical resistivity, the Hall coefficient and the magnetic susceptibility of amorphous alloys (Metglass 2826A, Allied Chemical) have been measured above room temperature. The experimental data show strong similarities with liquid alloys.     

Order-discharge transition in Ni3Fe alloy

The order-disorder phase transition in Ni₃Fe alloy (26.4 at.% Fe) is investigated experimentally, determining the transition temperature, the size of the antiphase domains, the temperature dependence of the degree of long-range order, and the lattice parameter. The differing and common features of the order -disorder transition in the alloys Ni₃Fe and Cu₃Au are discussed, and the temperature dependence of the degree of long-range order in these alloys is compared with theoretical predictions, including results obtained by the Green's function method in the present work.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 32–39, May, 1977.