The effects of impurity concentrations and temperature upon the parameter, le/ls, was studied in Pb-doped crystals. Here, le and ls were the free paths of edge and screw dislocations, respectively, in the stress field that was produced by an indenter. The results were explained in terms of an additional dragging that was due to the dislocation debris which was encountered by moving screw dislocations.

J.S.Boyarskara, R.P.Zhitaru, M.A.Linte: Kristallografiya, 1996, 41[4], 737-42 (Crystallography Reports, 1996, 41[4], 700-5)