Theory of magnetic field-induced charge-density-wave phases

We elaborate an analytical theory of a cascade of magnetic field-induced charge-density-wave (FICDW) phases. It is shown that the following features distinguish it from the well-known spin-density-wave cascade: (1) the FICDW phases exist at temperatures much lower than the characteristic CDW transition temperature at H=0; (2) the cascade of the FICDW phases dramatically changes at certain directions of a magnetic field due to an interplay of Zeeman spin-splitting and electron motion along open Fermi surfaces. Theoretical results are compared with the recent experimental attempts to reveal FICDW phases in the organic conductors α-(ET)₂MHg(SCN)₄(M=K, Tl, Rb, etc.).     

Interference commensurate oscillations in quasi-one-dimensional conductors

We suggest an analytical theory to describe angular magnetoresistance oscillations recently discovered in the quasi-one-dimensional conductor (TMTSF)2PF6 [see Phys. Rev. B 57, 7423 (1998)]] and define the positions of the oscillation minima. The origin of these oscillations is related to interference effects resulting from Bragg reflections which occur as electrons move along quasiperiodic and periodic ("commensurate") electron trajectories in the extended Brillouin zone. We reproduce via calculations existing experimental data and predict some novel effects.     

Soliton wall superlattice charge-density-wave phase in a magnetic field

A model where phase transitions between the Peierls and periodic soliton wall superlattice (SWS) charge-density-wave phases occur in a magnetic field is proposed. The model accounts for the peculiarities of the electron spectrum in a quasi-one-dimensional conductor (Per)₂Pt(mnt)₂. Possible experimental investigations of the theoretically predicted phase transitions in (Per)₂Pt(mnt)₂ to discover a unique SWS phase are discussed. The text was submitted by the authors in English.     

A two-regime probe-forming system for modern nuclear nanoprobes

This paper describes the long version of an optimized probe-forming system based on the divided Russian quadruplet of magnetic quadrupole lenses. The calculations include dominant intrinsic and parasitic lens aberrations. The feature of the system is a two-regime operation. This new versatile system is promising for modern nuclear nanoprobes. The system resolutions expected are presented.     

New method for sintering silica frits for capillary microcolumns

One of the main steps in the manufacture of robust and efficient packed capillary microcolumns for electro- and capillary chromatography is the generation of porous devices to retain the packed beds. Frits based on sintered silica particles have been found to give the best results in terms of mechanical resistance and efficiency. The conventional procedure to produce these kinds of frits consists in a radial heating of the packed material with either a flame or an electrical resistance, but the frits thus obtained have many drawbacks as a result of the procedure rather than the silica per se as the base material. In the present work we investigated a new approach to produce silica-based retaining devices involving the frontal exposure of a short silica-particle bed packed at the end of a capillary tube. The capillary is radially insulated and frontally exposed to the heat of a muffle oven, generating a transfer of heat that is not radial but rather throughout the capillary axis. This procedure resulted in substantial advantages: an improved radial homogeneity, a protection of the external polyimide, and a generation of extremely short (400–600 μm) frits that were highly permeable and avoided bubble formation.