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Monocrystalline thin layers of (Eu,Gd)Te, n-type ferromagnetic semiconductor, were grown by molecular beam epitaxy technique on BaF2 (111) substrates. Reflection high-energy electron diffraction, X-ray diffraction, and atomic force microscopy characterization proved epitaxial mode of growth and high crystal quality of the layers. Magnetic susceptibility and magnetic resonance measurements showed that in (Eu,Gd)Te layers ferromagnetic transition takes place at about 13 K. Electrical characterization carried out by the Hall effect and resistivity measurements revealed very high electron concentration of 10 20 cm −3 and sharp maximum of resistivity at transition temperature.

Photo-induced ESR has been investigated in the temperature range 150 to 300 K using nearly homogeneous optical excitation (hv N 1.3 eV). The relaxation of the photo-ESR shows, similarly to that of photoconductivity, two components which are approximately described by a logarithmical function of time, decay rate being enhanced with increasing temperature. The time and temperature dependences of the photo-ESR as well as the relationship between the photo-ESR and photoconductivity are interpreted on the basis of a model, with traps for electrons having various values of emptying energy continuously distributed in a certain energy range and two kinds of localized valence states.Photo-induzierte ESR wird zwischen 150 und 300 K mit nahezu homogener optischer Anregung (hv 1,3 eV) untersucht. Die Relaxation der Photo-ESR zeigt, ahnlich wie die der Photoleitung, zwei Komponenten, die durch eine logarithmische Zeitabhangigkeit niiherungsweise beschrieben werden konnen und deren Abklingrate mit steigender Temperatnr groBer wird. Die Zeit-und Temperaturabhangigkeit der Photo-ESR ebenso wie die Zusammenhange zwischen Photo-ESR und Photoleitung werden durch ein Model1 mit Elektronenhaftstellen unterschiedlicher Befreiungsenergie interpretiert, die kontinuierlich uber ein bestimmtes Energieintervall verteilt sind, und zwei Arten von lokalisierten Valenzzustanden.