Sub-grain boundaries and dissociations of dislocations in yttrium iron garnet deformed at high temperatures

Sub-grain boundaries in YIG single crystals deformed at high temperatures (0·8-0·9 TM) have been studied by transmission electron microscopy. Dislocation networks form mainly by climb; they are formed from dislocations with α/2 〈111〉 Burgers vectors. Dislocation junctions with α 〈100〉 Burgers vectors are usually found in networks; however, junctions with α 〈110〉 Burgers vectors are occasionally observed. They are dissociated into two partial dislocations with collinear Burgers vectors and the resulting fault configuration has been shown to be one corresponding to climb.