Published by the American Physical Society through the American Institute of Physics
Physical Review B, Condensed Matter and Materials Physics vol:76 issue:5
The decrease of the average magnetic grain size with increasing Ag spacer thickness was deduced recently [J. Balogh, D. Kaptas, L. F. Kiss, T. Pusztai, E. Szilagyi, A. Tunyogi, J. Swerts, S. Vandezande, K. Tenst, and C. Van Haesendanck, Appl. Phys. Lett. 87, 102501 (2005)] from bulk magnetic properties of Fe/Ag granular multilayers. Now we show detailed Mossbauer spectroscopy measurements that support this finding and determine the hyperfine fields of Fe atoms in the grain boundaries. The grain size estimated by a simple model from the grain boundary fraction agrees well with that obtained from the external field dependence of the hyperfine field in the superparamagnetic state.