Electron Paramagnetic Resonance of Cr in PbTe

We present the results of the low temperature electron paramagnetic resonance (EPR) and transport investigations of the crystals of Pb1x C r x T e (x < 0.01). The samples with chromium concentrations z 0.0015 are all n-type. For these samples we observe the single EPR line with the g-factor decreasing from g 1.97 till g = 1.93 with increasing carrier concentration. This resonance can be attributed to electrically and magnetically active Cr 3 + ions. The crystals with Cr concentration x 0.0015 may be both n-and p-type. The EPR spectrum of these samples consists of two lines: the one discussed above and the other one with g = 1.99 observed only for samples with electron concentration n 10 18 cm-3 .