To prove directly the relation between the emergence of narrow lines in the dislocation photo‐l uminescence spectrum of germanium after the second deformation stage and the splitting value Δ of perfect dislocations a special orientation of crystals at the second deformation stage is used. The samples contain dislocations either with Δ > Δ0 or with Δ < Δ0 (Δ0 is the equilibrium splitting value). The narrow lines are found to arise only on the short‐w ave side of the line corresponding to equilibrium splitting at Δ > Δ0 and on the long‐w ave side at Δ < Δ0. This result and the unique regularity of the narrow line arrangement observed experimentally are considered as a convincing evidence for the effect of the distance between partials on the radiation energy associated with the 90° partials only.

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The properties of Nb-doped YBa,Cu,O, ceramics obtained by thermolysis of the oxide or nitrate (Y, Ba, Cu) solution in ammonium nitrate melt were studied. For t h e composition YBa,Cu,~,Nb,,,,O,., , T, = 92 K and the transport critical current J , = 100&4000 A cm? were obtained. The magnetic flux profile was studied by a magneto-optic method at B = 290 G. Domains of size 200400 fin-were found with magnetic critical current J," = 2 x lo4 A cm-2 at 77 K and IO5 A cm-2 at 11 K.

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