Spiraling spin structure in an exchange-coupled antiferromagnetic layer

Using trilayers of permalloy/FeMn/Co with various thickness t(AF) Of the antiferromagnetic FeMn, we have observed evidence of a spiraling spin structure within FeMn. For t(AF) < 90 Angstrom, the turn angle theta of the spiral varies as theta = (1.76 degrees/Angstrom)t(AF).