PAD-INVESTIGATIONS ON MNS CLUSTER FORMATION WITHIN THE DILUTED MAGNETIC SEMICONDUCTOR ZNMNS

Perturbed angular distribution (PAD) measurements were performed on Zn 2-xMnxS (x = 0.05, 0.06, 0.10, 0.18, 0.21 and 0.23). In our PAD experi ments recoil-implanted Fe-54 ions were used as nuclear probes. By the local magnetic behaviour of the isolated Fe-54 nuclei we obtained info rmation on the probe environment. The crystal having the lowest mangan ese concentration (x = 0.05) shows only one hyperfine component. The t emperature dependence of this component is the same as in that case of pure ZnS. For samples with concentrations x greater-than-or-equal-to 0.06 two additional hyperfine components are observed. One of them is attributed to beta- or gamma-MnS clusters, respectively. The other add itional component occurs for crystals having Mn-concentrations x great er-than-or-equal-to 0.10. The behaviour of this component is similar t o the one observed with pure alpha-MnS. From our data we conclude that the additional components observed with Mn concentrations x greater-t han-or-equal-to 0.06 are due to the formation of different types of Mn S clusters. Our experimental findings are compared with the data of ma gnetic susceptibility, photoluminescence and EPR.