RESIDUAL-STRESS AND DOMAIN-STRUCTURE

Calculations show that as the residual stress increases, the number of magnetic domains in titanomagnetite at first increases and subsequent ly decreases, and large residual stress causes laminar domain structur es in Ti-rich titanomagnetite, as is often observed. In addition, larg e residual stress significantly decreases the number of domains, as is also observed. One anticipates that large residual stress also exists in most pure magnetites, but theory and observations are inadequate t o confirm this expectation. We conclude that the presence of a large m acrostress and possible systematic errors in the observational estimat es of the number of domains observed explains the current discrepancy between domain observations and theory for titanomagnetite grains.