29 research outputs found
Magnetic properties of Sn/1-x/Cr/x/Te diluted magnetic semiconductors
We present the studies of Sn/1-x/Cr/x/Te semimagnetic semiconductors with
chemical composition x ranging from 0.004 to 0.012. The structural
characterization indicates that even at low average Cr-content x < ?0.012, the
aggregation into micrometer size clusters appears in our samples. The magnetic
properties are affected by the presence of clusters. In all our samples we
observe the transition into the ordered state at temperatures between 130 and
140 K. The analysis of both static and dynamic magnetic susceptibility data
indicates that the spin-glass-like state is observed in our samples. The
addition of Cr to the alloy seems to shift the spin-glass-like transition from
130 K for x = 0.004 to 140 K for x = 0.012.Comment: 4 pages, 4 figure
Point defects and p-type conductivity in Zn1-xMnxGeAs2
Positron annihilation spectroscopy is used to study point defects in Zn1–xMnxGeAs2 crystals with low Mn content 0≤x≤0.042 with disordered zincblende and chalcopyrite structure. The role of negatively charged vacancies and non-open-volume defects is discussed with respect to the high p-type conductivity with carrier concentration 10exp19≤p≤10exp21cm−3 in our samples. Neutral As vacancies, together with negatively charged Zn vacancies and non-open-volume defects with concentrations around 10exp16−10exp18 cm−3, are observed to increase with increasing Mn content in the alloy. The observed concentrations of defects are not sufficient to be responsible for the strong p-type conductivity of our crystals. Therefore, we suggest that other types of defects, such as extended defects, have a strong influence on the conductivity of Zn1–xMnxGeAs2 crystals.Peer reviewe