MN-55, TE-125, AND CD-113 NMR-STUDIES OF THE DILUTED MAGNETIC SEMICONDUCTOR CD1-XMNXTE IN THE RANGE X = 0.01-0.6

Mn-55, Te-125, and Cd-113 NMR has been used in the diluted magnetic semiconductor Cd(1-x)Mn(x)Te (x = 0.01-0.6) for probing into local electronic structure. The detection of Mn-55 nuclei in the magnetically (3d5) and quadrupolar (I = 5/2) broadened NMR spectra has been possible only at low frequency because of the Mn2+-Mn2+ exchange interaction, particularly in the antiferromagnetic clusters for high values of x (0.125-0.6). Te-125, which undergoes transferred hyperfine interaction from Mn2+, could, however, be detected at high frequencies (94.88 MHz) for x = 0.6 and 0.3. At these high x values, exchange within the clusters reduces the effective magnetic moment <S(z)> experienced by Te and consequently the broadening is within limits. The situation is quite different in Cd-112, as Mn2+ is not the nearest neighbor nor is it bonded to Mn directly. However, it does undergo dipolar interaction with the Mn2+ spin and is also affected by the spin polarization of the sp band of CdTe by Mn2+. Thus Cd-113 NMR has been detected for all x values. The shift changes sign between x = 0.6 and x = 0.3 in both Mn and Te, from positive to negative in Mn and negative to positive in Te as expected for direct versus transferred hyperfine interaction. The shift also changes sign in Cd-113; as expected it parallels the Mn shift.