Volume 84, Issue 1, 01 July 1998
Index of content:
Effect of deposition temperature and growth rate on the bond structure of hydrogen free carbon films84(1998); http://dx.doi.org/10.1063/1.368091View Description Hide Description
The effect of deposition temperature and growth rate on the bond structure of hydrogen free carbonfilms has been investigated. A sharp transition temperature of the content of the carbonfilms as a function of deposition temperature has been reported several times. The value of this transition temperature has varied from 150 to about 300 depending on the growth mechanism. In this article, high values varying from 300 to 400 for the transition temperature are reported. High momentary growth rates of up to 2000 nm/s have been obtained by using pulsed vacuum arc deposition. The transition temperature has been observed to depend on the momentary growth rate of the carbonfilm. The transition has been explained to be a relaxation process which includes diffusion of carbon atoms at the near surface. The results have been analyzed by using a model which was originally developed for radiation enhanced diffusion. An activation energy of 0.65 eV was obtained. The model also predicts qualitatively the transition temperatures in the case of the lower deposition rates reported in literature. For the frequency factor of the diffusion coefficient a value of the order of was obtained.
84(1998); http://dx.doi.org/10.1063/1.368067View Description Hide Description
The magnetic and electronic transportproperties of the title compounds are systematically studied. Both compounds are found to have similar properties. The magnetic measurements are consistent with the mictomagnetic behavior. An insulator-to-metal transition is observed with decreasing temperature and the low temperature resistivity shows the metalliclike feature. It is proposed that apart from the already identified ferromagnetic metal and spin glassinsulator phases, the metalliclike mictomagnetic phase should exist at the boundary area between the two known phases in the universal phase diagram for the manganates.
High average-power THz radiation from femtosecond laser-irradiated InAs in a magnetic field and its elliptical polarization characteristics84(1998); http://dx.doi.org/10.1063/1.368068View Description Hide Description
The THz-radiation power from bulk InAs irradiated with femtosecond optical pulses is significantly enhanced and reaches 650 μW in a 1.7-T magnetic field with 1.5-W excitation power. The THz-radiation power is related almost quadratically both to the magnetic field and excitation laser power. We have also found that the power of the THz-radiation from an InAs sample in a magnetic field is over one order of magnitude higher than that from GaAs. Additionally, a dramatic change of ellipticity is observed, and the spectra of the horizontal and vertical polarization components are found to differ.