CORRELATION BETWEEN MAGNETIC AND ELECTRONIC-PROPERTIES OF SN1-XGDXTE

Magnetic susceptibility, electron paramagnetic resonance and transport properties of Sn1-xGdxTe with 0.04 < x < 0.07 and hole concentrations in the range from 0.7 x 10(20) to 16 x 10(20) cm(-3) were investigate d. After annealing of the Sn1-xGdxTe samples with x < 0.05 in Sn vapor their hole concentration decreased from 5 x 10(20) cm(-3) to about 3 x 10(20) cm(-3) and their paramagnetic Curie temperature increased a f ew times. In samples with x > 0.05 no significant change in the magnet ic properties was observed after annealing, even at lower hole concent rations. The results can be explained by assuming that an indirect exc hange interaction, 4f-5d-band electrons, is responsible for the coupli ng among Gd ions.