Abstract
A theoretical survey of lattice defects including transformation twins due to a structural transformation is presented for Mn3O4 hausmannite. Room-temperature transmission electron microscopy observations of synthetic samples reveals that accommodation twins are present, associated with the structural transition. Two types of {112} twin wall were found: coherent and incoherent twin walls, in agreement with theoretical predictions. Two types of undissociated perfect dislocation with Burgers vector (100) and 1/2(111) were identified, both corresponding to 1/2(110) Burgers vectors of perfect dislocations in the parent high-temperature spinel phase. Dislocations interact strongly with twin boundaries.