Delineation of defect structures in flux-grown GdFeO3 crystals by etching

Etch patterns on (<(11)over bar 0>) and (001) faces of as-obtained GdFeO3 c rystals are illustrated and described. Rectangular etch pits oriented with their longer sides in [100] direction and shorter sides in [010] direction are exhibited by [001] faces, whereas almost circular etch pits are exhibit ed by (<(11)over bar 0>) faces of as-obtained crystals. Hexagonal etch pits and triangular etch pits produced as a result of etching in boiling HNO3 o n (001) and (<(11)over bar 0>) faces are respectively illustrated. Evidence in support of twinning in some crystals is offered. The etch pattern on as -grown crystals are attributed to some fault in their growth conditions. Ed ge nucleated growth pyramids on a (<(11)over bar 0>) face and conical hillo cks on (001) faces exhibiting pits at the centres of their initiation are i llustrated. The conical hillocks are suggested to be as a result of prefere ntial growth at the point of emergence of screw dislocations. (C) 2000 Else vier Science B.V. All rights reserved.