Configuration of the atomic planes bordering a crack in the modified Peierls-Nabarro model

A crack model similar to the Peierls-Nabarro model is used to investigate the dependence of the configuration of the atomic planes bordering a crack on the law of interplanar interaction. The maximum stress at the end of the crack is determined directly from the stress law, and the configuration of the crack is described by a smooth function satisfying nonlinear integro-differential singular equation (1.3). A semi-inverse method of solving this equation is proposed. The configurations of the atomic planes bordering the crack are constructed for a series of laws of interplanar interaction.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, Vol. 11, No. 1, pp. 96–102, January–February, 1970.The authors thank Yu. N. Rabotnov for his interest in their work and A. A. Shtol'berg for assisting with the numerical calculations.     

X-ray detected magnetic resonance at the Fe K-edge in YIG: Forced precession of magnetically polarized orbital components

X-ray detected magnetic resonance (XDMR) has been measured for the first time on exciting the Fe K-edge in a high-quality yttrium iron garnet film epitaxially grown on a gadolinium gallium garnet substrate. This challenging experiment required resonant pumping of yttrium iron garnet at high microwave power, i.e., in the foldover regime. X-ray magnetic circular dichroism (XMCD) was used to probe the change in the longitudinal component of the magnetization M _Z induced by the precession of magnetic moments located at the iron sites. Since XMCD at the Fe K-edge refers mostly to the equilibrium contribution of magnetically polarized 4p orbital components, XDMR at the Fe K-edge should reflect the precessional dynamics of the latter orbital moments. From the measured precession angle, we show that there is no dynamical quenching of the polarized orbital components at the iron sites in yttrium iron garnet.     

Influence of columnar defects on the thermodynamic properties of BSCCO

Amorphous columnar defects strongly affect the reversible magnetization of Bi₂Sr₂CaCu₂O_8+δ single crystals both in the vortex solid, where the change reflects the change in vortex energy due to pinning, and in the vortex liquid, where the randomly positioned columns disrupt the interaction between superconducting fluctuations.     

Surface deformation due to non-homogeneous distribution of solute atoms in crystals

Deformation caused by a modulated distribution of solute atoms, periodic in one dimension, in a plate-like crystal is studied within the framework of the isotropic theory of elasticity. The exact formulae for the strain and displacement field, which changes near the surface due to relaxation of the internal concentration stresses, can be used for determination of the distribution of the solute atoms by X-ray diffraction techniques.     

Direct and inverse measurement of thin films magnetostriction

Two techniques of measurements of thin film magnetostriction are compared: direct, when changes of the substrate curvature caused by the film magnetization are controlled, and inverse (“indirect”), when the modification of the magnetic anisotropy induced by the substrate deformation (usually bending) is measured. We demonstrate how both the elastic strength of the substrate and the effective magneto-mechanical coupling between the substrate deformation and magnetic anisotropy of the film depend on different conditions of bending. Equations to be used for magnetostriction value determination in typical cases are given and critical parameters for the corresponding approximations are identified.     

A monopole mass filter with a hyperbolic V-shaped electrode

In this article we compare the classical monopole mass filter of von Zahn and the monopole mass filter with a hyperbolic V-shaped electrode. The experimental results and those of computer simulation for both mass spectrometers are presented. We show that the replacement of a conventional 90 degrees V-shaped electrode by an electrode with a hyperbolic profile substantially improves the peak shape of any given mass, and increases the mass resolution by a factor of 3-4 and the abundance sensitivity by a factor of 100. The potential of high analytical performance combined with electroforming techniques for electrode manufacture indicate future practical uses of such instruments. Copyright 1999 John Wiley & Sons, Ltd.     

Amorphous shear bands in deformed TiNi alloy

The structure and strain relief of TiNi alloy are examined following combined deformation consisting of quasi-hydro-extrusion followed by uniaxial compression. The shear nature of the amorphous bands resulting from such strain is demonstrated. A connection between the amorphous bands and the strain relief has been found. Fiz. Tverd. Tela (St. Petersburg) 39, 1237–1239 (July 1997)