Metal In Magnetic Field Research Articles

Corrosion mechanism and research progress of metal pipeline corrosion under magnetic field and SRB conditions: a review

Abstract Biocides are used to prevent microbiologically influenced corrosion (MIC), which damages and disables metal structures. However, biocides can make microorganisms resistant and contaminate the environment. Some studies have found that magnetic fields have an inhibitory effect on MIC, providing a new way of thinking for MIC control. In this paper, the current research status of MIC is discussed for typical anaerobic sulfate-reducing bacteria (SRB), the MIC of different metals in different environments is summarized, and the corrosion mechanism of SRB on metal structures, including cathodic depolarization and metabolite corrosion, is introduced. On this basis, the research progress of metal corrosion under magnetic field and microbial conditions in recent years is summarized, and discussed from three aspects, namely, electrochemical corrosion, SCC, and microbial corrosion, respectively. The corrosion process of microorganisms on metals in magnetic field is summarized, including biofilm theory, ion interference theory, free radical theory, and so on. Finally, the prevention and control of microbial corrosion by magnetic fields are prospected using the relevant mechanisms of magnetic field corrosion on metals.

High-order perturbation corrections to the density of states of disordered metals in a magnetic field

We study the effect of electron-electron interaction on one-particle density of states (DOS) ${\ensuremath{\rho}}^{(d)}(\ensuremath{\epsilon},T,\mathbf{B})$ of weakly disordered metals in magnetic field ($B$), employing the conventional impurity diagram technique. The geometric resummation of the most singular self-energy corrections via the Dyson equation is examined. Around the Fermi level ($\ensuremath{\epsilon}=0$), we obtain that the DOS is linearly dependent on energy, ${\ensuremath{\rho}}^{(2)}(\ensuremath{\epsilon},T=0,\mathbf{B})\ensuremath{\sim}|\ensuremath{\epsilon}|/B$, in two-dimensional systems while in three dimensions it acquires a power-law behavior, ${\ensuremath{\rho}}^{(3)}(\ensuremath{\epsilon},T=0,\mathbf{B})\ensuremath{\sim}{|\ensuremath{\epsilon}|}^{\frac{3}{4}}/B$. It is revealed that in both dimensions the DOS depends inversely on magnetic field strength at low energies and vanishes at the Fermi energy.

Weakly incoherent regime of interlayer conductivity in a magnetic field

We investigate the conductivity in layered metals in magnetic field in the weakly incoherent limit, when the interlayer transfer integral is smaller than the Landau level broadening due to the impurity potential, but the interlayer electron tunnelling conserves the intralayer momentum. It is shown that the impurity potential has much stronger effect in this regime, than in the quasi-2D metals in the coherent limit. The weakly incoherent regime has several new qualitative features, not found in the previous theoretical approaches. The background interlayer magnetoresistance in this regime monotonically grows with increasing of magnetic field perpendicular to the conducting layers. The effective electron mean free time is considerably shorter than in the coherent regime and decreases with magnetic field. This enhances the role of higher harmonics in the angular magnetoresistance oscillations and increases the Dingle temperature, which damps the magnetic quantum oscillations.

Non-equilibrium statistical theory about microscopic fatigue cracks of metal in magnetic field

This paper develops the non-equilibrium statistical fatigue damage theory to study the statistical behaviour of micro-crack for metals in magnetic field. The one-dimensional homogeneous crack system is chosen for study. To investigate the effect caused by magnetic field on the statistical distribution of micro-crack in the system, the theoretical analysis on microcrack evolution equation, the average length of micro-crack, density distribution function of micro-crack and fatigue fracture probability have been performed. The derived results relate the changes of some quantities, such as average length, density distribution function and fatigue fracture probability, to the applied magnetic field, the magnetic and mechanical properties of metals. It gives a theoretical explanation on the change of fatigue damage due to magnetic fields observed by experiments, and presents an analytic approach on studying the fatigue damage of metal in magnetic field.

The Phase Diagram and the Structure of the Charge-Density-Wave State in High Magnetic Field

The properties of a charge-density wave (CDW) state in quasi-one-dimensional metals in magnetic field below the transition temperature are studied using the mean-field theory. We calculate the phase diagram and show that the CDW state with shifted wave vector in high magnetic field (CDWx phase) has at least double-cosine modulation on the most part of the phase diagram. The transition from CDW0 to CDWx state below the critical temperature is accompanied by a jump of the CDW order parameter and of the wave vector rather than by their continuous increase. This implies a first order transition between these CDW states and explains the strong hysteresis accompanying this transition in many experiments. We examine how the phase diagram changes in the case of imperfect nesting. The results are applicable to different families of organic metals.

Local geometry of the Fermi surface and the cyclotron resonance in metals in a normal magnetic field

In this paper we present a detailed theoretical analysis of the cyclotron resonance in metals in the magnetic field directed along a normal to the surface of a sample. We show that this resonance occurs due to local geometry of the Fermi surface of a metal. When the Fermi surface (FS) includes segments where its curvature turns zero or diverges, this could give rise to resonance features in the frequency/magnetic field dependence of the surface impedance or its derivative with respect to the field. Otherwise the resonance is scarcely detectable unlike the well-known cyclotron resonance in a parallel magnetic field. The proposed theory agrees with experimantal results concerning both convenient and organic metals.

The anomalies of the longitudinal magnetothermoelectric power of metal in the vicinity of electronic topological transition

The longitudinal magnetothermoelectric power (MTEP) is calculated for metal in magnetic field and in the vicinity of electronic topological transition (ETT). The giant oscillations of MTEP as a function of applied magnetic field are found. These oscillations originate from the energy dependence of electron relaxation time in magnetic field and they are peculiar to any normal metal independently of the shape of its Fermi surface. Nevertheless the ETT essentially changes the form and magnitude of such oscillations. The results of recent experimental investigation of MTEP in cadmium monocrystals under the pressure and in magnetic field are discussed from the point of view of the presented theory.

Low temperature electron transport properties of metals in magnetic field

The general relations between experimentally determined quantities and transport coefficients appearing in phenomenological transport equations were studied considering different orientations of magnetic field. Further relations are presented for the case of elastic scattering and special attention is paid to the alternative forms of the formulae of the Mott's type where the resistivity and its derivative are used instead of conductivity and its derivative. This new forms are shown to allow more straightforward analysis of magnetothermoelectric effects and, in the region of validity of Kohler rule, they make possible to gain information about their behaviour as functions of magnetic field. Several simple experimental arrangements are suggested for determination of the electronic transport properties of metals and alloys.

Effective electric conductivity tensor of polycrystalline metals in high magnetic fields

General equations with unknown parameters are obtained for the effective electric conductivity tensor of polycrystalline mixtures. Different methods of obtaining the unknown parameters are discussed. One of these methods, called in the paper the Bruggeman-Odelevsky method, has been applied to polycrystalline metals in a magnetic field. The influence of three different factors 1) fluctuations of the electron density 2) open orbits, 3) extended orbits, on the galvanomagnetic properties of a polycrystal has been investigated. In the first case agreement is found with Herrng's results, although it is shown that the range of applicability of his method is very restrained. The second case has not been considered by other authors. In the third case it is shown that the averaging method used by earlier authors needs very strong assumptions and this makes their explanation of the linear growth of the magnetoresistance doubtful.

Quantum theory of the electrical conductivity of metals in a magnetic field

The paper gives a consistent quantum-mechanical theory of the electrical conductivity of metals in magnetic fields. A kinetic equation is deduced for the statistical operator with general assumptions on the energy spectrum of electrons, and the limit of the transition to a classical case is analysed. Asymptotes of the kinetic coefficients in strong magnetic fields are studied. Starting from the established relationship between the solutions of quantum and classical equations, quantum corrections to the kinetic coefficients, which include resistance and conduction oscillations, are determined.

Electrical Resistance of Nickel and Permalloy Wires as Affected by Longitudinal Magnetization and Tension

The changes in the electrical resistance of ferromagnetic metals in magnetic fields and under mechanical stresses are abnormal in comparison with such changes in non-ferromagnetic metals. Published results for nickel and nickel-rich alloys, reviewed in detail, show wider diversity than can be ascribed to accident. A full bibliography is included.Simple cases of these magneto-resistance and elasto-resistance effects have been studied in permalloys containing from 45 to 90 percent nickel. The results of two series of experiments, in 1923 and 1929, are presented, and show that both effects have, in these ferromagnetic alloys, the same origin. This common origin can be considered as the orientation, by one means or the other, of atomic magnetic axes associated in each atom with mechanical asymmetry.The connection between these resistance effects and magnetostriction is emphasized. Conclusions are drawn as to the kinds of re-orientation involved in magnetizing and as to the relative importance in the observable effects of intra-atomic and interatomic magnetic fields. Questions for further experiment are raised.