X-ray investigation of the mechanisms of phase transformations in single crystals of ZnS, Zn_xCd_1-xS and Zn_xMn_1-xS (II). comparison of observed and calculated diffraction effects

Abstract

The experimentally observed intensity profiles recorded from ZnS, Zn_xCd_1-xS and Zn_xMn_1-xS crystals at different stages of the 2H-3C and 2H-6H transformations are compared with those computed theoretically from the three parameter model in the previous paper. It is found that the 2H-3C and 2H-6H transformations occur by the nonrandom nucleation of deformation faults. The probability of the growth of a nucleus is much greater than that of the creation of a fresh nucleus. At least two different fault probabilities have therefore to be employed in computing the diffraction effects in each case. The transformation behaviour of Zn_xCd_1-xS and Zn_xMn_1-xS crystals is strongly influenced by variations in stoichiometry (x). Large values of x (x > 0.95) favour the 2H-3C transformation, whereas smaller values (x ≤ 0.94) favour the formation of the 6H phase. A comparison of the calculated and observed intensity distributions indicates that in some crystals the 2H-3C and 2H-6H transformations occur simultaneously in different regions of the same single crystal.