Chaos in the Ferromagnetic Phase of a Reentrant Ferromagnet

Abstract

The inherent dynamic properties of the ferromagnetic phase of a reentrant ferromagnet, (F${\mathrm{e}}_{0.20}$N${\mathrm{i}}_{0.80}$${)}_{75}$${\mathrm{P}}_{16}$${\mathrm{B}}_{6}$A${\mathrm{l}}_{3}$, have been experimentally investigated by low field magnetic relaxation and ac susceptibility measurements. A prominent aging behavior and an apparent fatal fragility to temperature fluctuations imply that the ferromagnetic phase of the reentrant system has a chaotic nature similar to the spin glass phase, but in striking contrast to the robust nature of the regular ferromagnetic phase.