Microscopic Structure of Cleavage Surface of Ferroelectric Tri-Glycine Sulfate

The cleavage surface of TGS was examined by electron microscopy utilizing the low angle shadow decoration technique. The cleavage plane, in the unit cell, is the positive side of the layer of SO 4 -glycine 1. When the cleavage direction changes across the direction perpendicular to the (101) plane, the cleavage plane changes discontinuously by the amount b 0 /2, where b 0 is the unit cell length along the b -axis. The step of b 0 in height is bisected into smaller steps by cleavage along this direction. The elementary step formation, the inclination of the cleavage surface and the step bending at the domain boundary are interpreted synthetically by assuming that the bonding on the positive side of the crack front is more easily broken than that on the negative side by the cleavage along the c -axis.