Aging, memory, and nonhierarchical energy landscape of spin jam

TL;DR

This paper investigates the energy landscape of spin jam states in frustrated magnets, revealing weaker memory effects than spin glasses and proposing a nonhierarchical landscape model to explain their dynamics.

Contribution

It introduces a nonhierarchical energy landscape model for spin jam states, contrasting with the hierarchical model of spin glasses, supported by susceptibility measurements and Monte Carlo simulations.

Findings

Spin jam states show weaker memory effects than spin glasses.

A nonhierarchical, nearly flat energy landscape explains the observed dynamics.

Memory effects can serve as probes for different glassy energy landscapes.

Abstract

The notion of complex energy landscape underpins the intriguing dynamical behaviors in many complex systems ranging from polymers, to brain activity, to social networks and glass transitions. The spin glass state found in dilute magnetic alloys has been an exceptionally convenient laboratory frame for studying complex dynamics resulting from a hierarchical energy landscape with rugged funnels. Here, we show, by a bulk susceptibility and Monte Carlo simulation study, that densely populated frustrated magnets in a spin jam state exhibit much weaker memory effects than spin glasses, and the characteristic properties can be reproduced by a nonhierarchical landscape with a wide and nearly flat but rough bottom. Our results illustrate that the memory effects can be used to probe different slow dynamics of glassy materials, hence opening a window to explore their distinct energy landscapes.