Excess specific heat and evidence of zero point entropy in magnetic glassy state of half-doped manganites

TL;DR

This study reveals that magnetic glassy states in half-doped manganites exhibit excess specific heat, non-Debye behavior, and zero point entropy, suggesting tunneling phenomena similar to conventional structural glasses.

Contribution

It demonstrates the presence of excess specific heat and zero point entropy in magnetic glasses of manganites, highlighting their similarity to conventional glasses and their unique thermodynamic properties.

Findings

Magnetic glasses show higher specific heat than equilibrium states.

Excess specific heat varies linearly with temperature, indicating tunneling effects.

Presence of zero point entropy in magnetic glassy states.

Abstract

We show that specific heat C$_p$ has non-Debye behavior for glassy states in half-doped manganites. Irrespective of the magnetic order or electronic states, these magnetic glasses have higher C$_p$ compared to their equilibrium counterparts. The excess C$_p$ contributed by the glassy state varies linearly with temperature similar to conventional glasses indicating tunneling in the two-level systems. These glassy states show signature of zero point entropy. Magnetic glasses can be produced simply by different field cooling protocols and may be considered ideal magnetic counterpart of the conventional glass.