Unusual Magnetic Relaxation in SuperfluidHe3

Abstract

Pulsed-NMR measurements of the longitudinal spin-relaxation time $T_1$ in superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ are reported which indicate that new and very unconventional relaxation mechanisms exist below $T_c$. In $A$-${}_{}{}^3{}_{}{}^{}\mathrm{He}$, $T_1$ decreases very rapidly below $T_c$ and the magnetization recovery from saturation is linear in time. In $B$-${}_{}{}^3{}_{}{}^{}\mathrm{He}$, the magnetization recovery is exponential in time, but the relaxation rate $\frac{1}{T_1}$ is linear in applied field gradient. Possible explanations of these phenomena are discussed.