Evidence for dipolar effects in re-entrant amorphous ferromagnets

Abstract

Comprehensive high-resolution magnetic susceptibility measurements on amorphous ferromagnets, which either do or do not exhibit re-entrant behavior at low temperatures, for the first time, clearly bring out the importance of isotropic dipolar interactions in establishing long-range ferromagnetic order in re-entrant amorphous ferromagnets and offer a possible way of solving the long-standing re-entrant spin-glass paradox by convincingly explaining why the ferromagnetic state possesses larger entropy than the re-entrant spin-glass state in such systems.