By means of time differential perturbed angular correlation spectroscopy, we studied the 111Cd hyperfine fields in molecular beam epitaxy-grown Fe/Co multilayers on (1–10) GaAs as a function of temperature (90–570 K). Together with the known fields for Cd in bcc Fe and in bcc Co, we observed 4 sharply defined satellite fields. They have previously been associated with probe positions near a sharp Fe/Co interface. Whereas the Cd hyperfine field in Fe and its satellites decrease with temperature, the satellites on the Co field increase with temperature as the CdCo field does. We determine values for the near interface moments by using them as free parameters when fitting the experimental satellite fields within a semiempirical model for the hyperfine field. At all temperatures, the Fe and Co magnetic moments near the sharp interface between bcc Fe and the monoclinically deformed body centered Co oscillate as a function of the layer number over 2 layers in Co and 3 in Fe. The near interface magnetic moments temperature dependence scales to one of atoms in bulk Fe and Co, respectively: in the investigated temperature range, all Fe moments decrease as (1−A×T3/2) while the Co moments are temperature independent.
By implanting B+ and O+ ions respectively into polycarbonate (PC) plates, the sur-face mechanical properties of PC have been improved. Measurement by Nano IndenterⅡ showed that the hardness of samples increased 7-25 times than that before implan-tation; and the modulus of elasticity raised 2-5 times. The wear-resistance was testedby ball crusher; the width and depth of the wear-streak decreased by 1/3-1/2 or evenmore. The structure, deformation and appearance were analyzed by using Micro-FTIR Spectra, ESCA method and the steps instrument. These analyses showed thatthe structure of PC had been modified: a series of new cross-linking yielded, it de-pends on the Linear Energy Transition (LET) of implanted ions in the high polymercompounds.
We report on the lattice location of Pr in thin film, single-crystalline hexagonal GaN using the emission channeling technique. The angular distribution of β− particles emitted by the radioactive isotope Pr143 was monitored by a position-sensitive electron detector following 60 keV room temperature implantation of the precursor isotope Cs143 at a dose of 1×1013 cm−2 and annealing up to 900 °C. Our experiments provide direct evidence that Pr is thermally stable at substitutional Ga sites.
The reaction of Co with epitaxial SiGeC/Si layers is investigated and compared to the reaction of Co with SiGe/Si layers. The sequence of phase formation is the same as the reaction of Co with monocrystalline Si, however, cobalt disilicide is formed at much higher temperatures. The presence of C further delays the disilicide formation, as a result of C accumulation at the silicide/substrate interface during the reaction, which blocks the Co diffusion paths. The CoSi2 layers thus formed exhibit a preferential (h00) orientation. The slow supply of Co atoms to the silicide/Si interface, due to the blocking of Co diffusion paths by Ge and C, is believed to be the reason for this epitaxial alignment.
