A MU-PROPERTIES OF FERRITIN(SR STUDY OF THE MAGNETIC)

We present a study of the magnetic properties of the superparamagnetic ferritin system by employing zero-field (ZF) and longitudinal-field ( LF) mu(+)SR measurements. Two mu(+) fractions with different depolaris ation behaviour are detected, one arising from muons stopped in the or ganic shell and one from muons stopped in the mineral core. The freezi ng of the superparamagnetic moments is evident in the temperature evol ution of the ZF relaxation rates of both fractions. It occurs graduall y below approximate to 60 K and is essentially complete at approximate to 11 K. The results are consistent with a distribution of blocking t emperatures which in turn reflects the distribution of core sizes.