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In-quadrature frequency-resolved photocurrent (FRPC) measurements were performed on amorphous (a-) As 2 Te 3 thin films between 20 K and 290 K, and as a function of excitation intensity. These measurements yield lifetime distributions directly. We have obtained a recombination lifetime of about 8 µs for a-As 2 Te 3 . This lifetime was found to be independent of excitation intensity and temperature. It is explained in terms of the capture of nonequilibrium carriers. We also present the temperature and intensity dependences of the FRPC response of a-As 2 Te 3 at a constant modulation frequency. They give information about recombination kinetics.

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The in-plane magnetization of a two-dimensional film may be stabilized by either, dipolar interacrions or by an in-plane anisotropy in the absence of an extemal field. We have calculated the conditions for eilher of these effects to dominate and show that there is only a restricted range of q values in which dipolar effects are important before the exchange dominates.We repotr,measurements of all relevant anisotropy fields for an epitaxial A@ ML CdAg(O0I) him structurally characterized by angle-resolved Auger spectroscopy and low-energy electron diffraction, together with a meaSuremen1 of the ground state momenc per CO atom (enhanced from the bulk value) using polarized neutron reflection. The resoh allow us to extend OUT previous study of lhe temperature dependence of the magnetization by including the perpendicular fields and the field dependence of the magnetization at 300 K. We show that the field dependence of lhe magnetization is not consistent with a spin wave gap due to dipolar interactions but is consistent with an~anisotropy-induced spin wave gap, confirming the results of a preliminary study.