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.     

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.     

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.     

Impurity effect of Me=Cr,Nb or Mn third component atoms on hyperfine interactions in ordered Ni3Fe alloy

Investigations of atomic ordering in Ni₃Fe, Ni₃(Fe, Nb), Ni₃(Fe,Cr) and Ni₃(Fe, Mn) alloys at room temperature in disordered and ordered states have been carried out by Mössbauer spectroscopy method. The experimental results confirm that in case of Ni₃Fe superstructure stabilization is achieved by Nb and Mn atoms, the Cr atoms disturb this structure.     

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.     

Investigation of the electronic characteristics of Ni3 (Fe,Ti) and Ni3 (Mn,Ti) alloys

The anomalous Hall (R_s) and the Nerst-Ettingshausen (Q_S) constants are measured for hardened Ni₃ (Fe, T_i) and Ni₃ (Mn, Ti) alloys. Scattering by phonons is detected, con tributing primarily to R_S as compared to scattering by magnetic inhomogeneities. Based on the positive signs of R_g and Q_S, it is concluded that 3d holes wi th antiparallel spin make the main contribution to the conductivity. A model is proposed for the electronic structure of the alloys studied.DeceasedTranslated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 59—63, June, 1981.     

Investigation of electronic configurations of Ni3(Fe,Ti) and Ni3(Mn,Ti) alloys

The ordinary Hall constant R_o of quenched Ni₃(Fe, Ti) and Ni₃(Mn, Ti) alloys was measured. The number of 4s and 3d electrons per atom was calculated on the basis of a four-band model. At low Ti concentrations in Ni₃(Fe, Ti) the contribution of 3d holes to R_o is negligible, but at high concentrations it is significant. The contribution of 3d holes to R_o for Ni₃(Mn, Ti) is considerable, and for Ni₃Mn and Ni₃(Mn +9.8% Ti) it is dominant. It is concluded that the changes in band energy of the bond between Ni and Ti in the considered systems are of a different nature.Deceased.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 12–14, May, 1981.     

Investigation of electrical resistivity and average magnetic moment per atom of Ni3(Fe,Ti) and Ni3(Mn,Ti) alloys

The electrical resistivity and average magnetic moment per atom of Ni₃(Fe, Ti) and Ni₃(Mn, Ti) alloys were measured. X-ray structural analysis revealed the presence of the Ni₃Ti phase in Ni₃(Fe+7% Ti) and Ni₃(Fe + 10.3% Ti), and strong interaction of Ni and Ti is deduced. The introduction of Ti into Ni₃Mn reduces the antiferromagnetic Mn-Mn interaction and thus leads to greater ordering.Deceased.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 9–12, May, 1981.     

Sensitivity of ordering kinetics to the doping of Ni3Mn by iron,cobalt, and chromium

The changes in several physical and mechanical properties observed during the ordering of quenched ternary Ni₃Mn-Ni₃Me alloys (Me = Fe, Co, or Cr) were studied. Comparison of the results with results found previously by neutron diffraction shows that the latter method does not always give reliable information about the state of the ordering of ternary alloys, so it must be supplemented by a study of structure-sensitive physical and mechanical properties.Translated from Izvestiya VUZ. Fizika, No. 10, pp. 116–124, October, 1969.     

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.     

Acceleration of ordering in iron-, cobalt-, and chromium-doped Ni3Mn

The various factors which can affect ordering in alloys are analyzed. The results of the analysis are applied to the ordering in Ni₃(Mn, Me) (Me = Fe, Co, or Cr) alloys. It is concluded that the accelerated ordering in these cases is caused by a change in the ordering mechanism from a homogeneous mechanism in Ni₃Mn to a heterogeneous mechanism in the ternary alloys and by an increase in the vacancy concentration due to doping.Translated from Izvestiya Vysshikh Uchebnykh Zavadenii Fizika, No. 1, pp. 73–78, January, 1970.     

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.     

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.     

Kinetics of ordering in Ni3Mn alloy with additions of copper

Neutron-diffraction analysis and measurements of electrical resistance were used to investigate the kinetics of ordering in Ni₃(Mn, Cu) alloys preliminarily tempered at 900°C, containing 0.45–9.29 at.% copper. It was established that introducing copper atoms in place of manganese atoms in the alloy Ni₃Mn leads to slowing of the ordering process. The degree of long-range order inside antiphase domains in Ni₃(Mn, Cu) alloys is less than in the binary alloy.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 35–39, March, 1977.     

Order-disorder transformation mechanism in aluminum-doped Ni3Mn alloy

The kinetics of order-disorder transformation in Ni₃(Mn, Al) alloys prequenched from 700°C has been studied by neutron-diffraction analysis. Within the framework of the I. M. Lifshits model, it is shown that in Ni₃(Mn, Al) alloys containing 2.0 and 4.3 at.% aluminum, ordering proceeds by the homogeneous mechanism at 400° and by nucleation and growth at 450°. The causes are discussed of the sharp speedup of the order-disorder transformation in its first stage in aluminum-doped Ni₃Mn alloy as compared with the binary alloy.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 24–28, April, 1977.     

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.     

Saturation magnetization and magnetostriction of Ni3Mn alloys containing aluminum and copper

An experimental investigation was made into the influence of the addition of copper and aluminum on the saturation magnetization J_s and magnetostriction _s of the Ni₃Mn alloy. It is shown that the behavior of J_s and _s depends on the distribution of the atoms of the added element over the sites of the fcc lattice of the Ni₃Mn alloy.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 29–33, February, 1981.We should like to thank A. I. Lotkov for the alloys made available for investigation.     

Some regularities of the fracture of ordered alloys based on Ni3Fe

Some regularities of the fracture of ordered polycrystals of the alloys Ni₃Fe, Ni₃(FeMn), Ni₃FeAl), Ni₃(FeCr), Ni₃(FeCr) are studied. The alloys Ni₃Fe, Ni₃(FeMn), and Ni₃(FeAl) possess low plasticity in the ordered state at the test temperatures T < 100 °C. In the 100–200 ° C temperature range a brittleness-viscosity transition is detected which is analogous to that observed in body centered cubic (BCC) metals and alloys. The transition from the brittle into the plastic state is not accompanied by a change in the metallographic picture of slip. The distinguishing peculiarity of the strain at elevated temperatures is the significant displacement of the grains along the boundaries. The temperature band of the transition from the brittle into the plastic state of ordered alloys in the tempered state (tempering from a temperature below the temperature of the order-disorder transformation) is observed at tempering temperatures above 450 °C (tests at room temperature). The results obtained permit the assumption that a reduction in the plasticity in ordering alloys based on Ni₃Fe is caused by segregation of the impurities along the grain boundaries.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 6, pp. 35–41, June, 1971.     

Effect on alloying at the Fe/Ni(001) interfaces on the interlayer exchange coupling

We investigate the stability of various ordered FeNi alloys at the interfaces of Fe/Ni superlattices by using ab initio density functional calculation. We consider an Fe_0.5Ni_0.5 ordered alloy of one or two monolayers thick at different positions beyond the interface and the possibility of an interdiffusion of a complete monolayer of Ni(Fe) in Fe(Ni) slab. An interfacial atomic layer of Fe_0.5Ni_0.5 exchanged with its adjacent Ni monolayers, leading to a buffer zone of Ni₃Fe composition is found to be the most stable structural configuration. For this atomic arrangement we investigate the magnetic profile and the resulting interlayer exchange coupling between the Ni slabs for Fe spacer thickness of 0 to 4 monolayers.