Effect of Local Anisotropy Fluctuation on the Permeability of Multilayered Co-Zr-Mo-Ni Amorphous Films
To evaluate the magnetic inhomogeneities normally represented as magnetic skew and ripple, a systematic experimental investigation was carried out using the dynamic differential susceptibility measurement proposed by H. Hoffmann for multilayered CO79Zr10Mo9Ni2 amorphous films. The influence of the local magnetic anisotropy on the effective permeability μeff of the films is broadly discussed in connection with the magnetic skew and ripple. The magnitude of the μeff in low frequency regions less than 1 MHz is strongly dependent on the degree of the long period fluctuation of the local magnetization direction (skew) and the magnitude of the anisotropy field. To realize excellent soft magnetic properties in films at high frequencies (10 MHz), it is suggested that the alleviation of magnetic inhomogeneities due to the short-period fluctuation of the local magnetization direction is important.
The Effective Field and the Differential Susceptibility in Ferromagnetic Films
A theory of the differential susceptibility is given for two-dimensional ferromagnetic samples. The susceptibility depends on the intrinsic demagnetizing field which is caused by the magnetization inhomogeneities. The susceptibility is related to the mean “effective field” as well as to the magnetization fluctuation. Its measurement can be used to determine quantitatively these properties which are related to the structure constant, S. The latter results from the inhomogeneity of the anisotropy. 
 
 
 
Es wird eine Theorie der differentiellen Suszeptibilitat in zweidimensionalen ferromagnetischen Proben hergeleitet, um damit die Anwendungsmoglichkeiten quantitativer mikromagnetischer Berechnungen aufzuzeigen. Die Suszeptibilitat in schwachen auseren Feldern wird wesentlich mitbestimmt durch das von Probeninhomogenitaten verursachte innere entmagnetisierende Feld. Die Suszeptibilitat ist mit dem „Effektivfeld” und den Schwankungen der Magnetisierungsrichtungen eng verknupft und kann zur Ermittlung beider Grosen herangezogen werden. Beide werden durch die Strukturkonstante S bestimmt, in welcher die inhomogenen Energieanteile der Probe zum Ausdruck kommen.
Neutron Residual Stress Measurements on Rail Sections for Different Production Conditions
Rail sectioning with subsequent neutron diffraction experiments has been used to assess residual stresses in the rails. In this study we present the results of neutron stress measurements performed at the NIST Center for Neutron Research (NCNR) on rail sections from rails that were produced under various conditions. Specifically, these are air-cooled, air-cooled and roller-straightened, head-hardened and head-hardened and roller-straightened. More significantly, a head-hardened and roller-straightened rail was also studied after service to elucidate evolution of the service-induced residual stresses. In the latter case both a transverse-cut slice and the central region of a 0.53 m long piece were studied. Measurements on this piece are the first in which triaxial stresses have been determined for an intact rail. Neutron strain measurements with 3×3×3 mm3 spatial resolution were successfully employed for transversally cut slices to verify the difference in the stress state depending on the production process. Although examination of slices allows determination of only two-dimensional stresses in the plane of the slice, additional measurements on obliquely-cut slices, which were also carried out, and utilization of FEM gives the possibility of reconstructing the full triaxial stress distribution. Together, these approaches provide a better understanding of rail fabrication and the possibility of improving the durability and safety of rails in the future.Copyright © 2004 by ASME