Sensitivity to temperature perturbations of the ageing states in a re-entrant ferromagnet

TL;DR

This study explores how temperature perturbations affect the aging and magnetic relaxation in a re-entrant ferromagnet, revealing phase-dependent asymmetries similar to those in spin glasses.

Contribution

It provides new insights into the temperature sensitivity of aging states in re-entrant ferromagnets, highlighting differences between ferromagnetic and spin glass phases.

Findings

Symmetric response to temperature cycles in the ferromagnetic phase.

Asymmetric response at low temperatures resembling spin glass behavior.

Temperature perturbations significantly influence magnetic relaxation in the spin glass phase.

Abstract

Dynamic magnetic properties and ageing phenomena of the re-entrant ferromagnet (Fe0.20Ni0.80)75P16B6Al3 are investigated by time dependent zero field cooled magnetic relaxation, m (t), measurements. The influence of a temperature cycling (perturbation), +/- *T, (prior the field application) on the relaxation rate is investigated both in the low temperature re-entrant spin glass 'phase' and in the ferromagnetic phase. In the ferromagnetic phase the influence of a positive and a negative temperature cycle (of equal magnitude) on the response is almost the same (symmetric response). The result at lower temperatures, in the RSG 'phase' is asymmetric, with a strongly affected response for positive, and hardly no influence on the response for negative temperature cycles. The behaviour at low temperatures is similar to what is observed in ordinary spin glasses.