Twin structures in lanthanum, praseodymium, and neodymium aluminate ceramics

Ferroelastic twins in LaAlO3 (LAO), PrAlO3 (PAO), and NdAlO3 (NAO) ceramics were investigated using transmission electron microscopy. In all three mat erials, (100) twin formation was favored over (110) twins. To confirm the p redominance of (100) twins, strain tensors for the two twins were calculate d. These calculations demonstrated that (100) twins relieve more strain inh erent in the twinned grain than (110) twins. It was observed that, from LAO to NAG, the twin shape was changed from wedge to lamellar, and that the tw in width was decreased for a given grain. These results were attributed to the increased lattice distortion from LAO to NAG. (C) 2001 Elsevier Science Ltd. All rights reserved.