Magnetostriction Behavior of Pseudobulk CoFeBSiNb(Ga) Systems
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
Authors: Hosko, J.; Janotova, I.; Svec, P.; Vlasak, G.; Matko, I.; Janickovic, D.; Gemming, T.; Stoica, M.; Svec, P., Sr.
Co-based ferromagnetic amorphous systems prepared by rapid quenching are parts of a very interesting group of materials from the perspective of new magnetic application possibilities. Practical applications of amorphous metallic glasses are in some cases limited by the thickness of the ribbon. In the present contribution as-cast and after annealing Co-Fe-B-Si-Nb ribbons (monolayer), pseudobulk (bilayer, trilayer) materials with increased thickness in comparison with ribbons (monolayer) and Co-Fe-B-Si-Nb-Ga ribbon were investigated by measurements of magnetostriction lambda (s) . These materials were prepared by planar flow casting method (PFC) and modified PFC method with a single crucible which has two or three nozzles for preparation of pseudobulk samples, respectively. The field dependence of the parallel [lambda (par)(H)] and perpendicular [lambda (perp)(H)] magnetostrictions in the sample plane was measured at room temperature. These dependencies were used to calculate the values of saturation magnetostriction lambda (s) . Microstructure of the as-cast samples as well as annealed samples was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM).
Relative vibrational overtone intensity of cis-cis and trans-perp peroxynitrous acid
JOURNAL OF CHEMICAL PHYSICS
Authors: Matthews, J; Sinha, A; Francisco, JS
The vibrational overtone spectrum of HOONO is examined in the region of the 2nu(OH) and 3nu(OH) bands using action spectroscopy in conjunction with ab initio intensity calculations. The present measurements indicate that the oscillator strength associated with the higher energy trans-perp conformer of HOONO is stronger relative to the lower energy cis-cis conformer for both these vibrational overtone levels. Ab initio intensity calculations carried out at the QCISD level of theory suggest that this disparity in oscillator strength apparently arises from differences in the second derivative of the transition dipole moment function of the two isomers. The calculations indicate that the oscillator strength for the trans-perp isomer is similar to5.4 times larger than that of the cis-cis isomer for the 2nu(OH) band and similar to2 times larger for 3nu(OH) band. The band positions and intensities predicted by the calculations are used to aid in the assignment of features in the experimental action spectra associated with the OH stretching overtones of HOONO. The observed relative intensities in the experimental action spectra when normalized to the calculated oscillator strengths appears to suggest that the concentration of the higher energy trans-perp isomer is comparable to the concentration of the cis-cis isomer in these room temperature experiments. (C) 2004 American Institute of Physics.