A reentrant phenomenon in magnetic and dielectric properties of Dy2BaNiO5 and an intriguing influence of external magnetic field

TL;DR

This study reveals a reentrant multiglass phenomenon in Dy2BaNiO5, showing unique magnetic and dielectric responses at low temperatures influenced by external magnetic fields, highlighting novel magnetoelectric coupling behavior.

Contribution

It uncovers a reentrant multiglass behavior in an undoped spin-chain compound and demonstrates how magnetic fields differently affect magnetic and dielectric features at low temperatures.

Findings

Magnetic susceptibility and dielectric properties show frequency-dependent behavior below 10K.

External magnetic fields shift magnetic and dielectric features in opposite directions.

The magnetic feature moves to higher temperatures, while the dielectric feature shifts lower with increasing magnetic field.

Abstract

We report that the spin-chain compound Dy2BaNiO5 recently proven to exhibit magnetoelectric coupling below its Neel temperature (T_N) of 58 K, exhibits strong frequency-dependent behavior in ac magnetic susceptibility and complex dielectric properties at low temperatures (<10K), mimicking 'reentrant' multiglass phenomenon. Such a behavior is not known among undoped compounds. A new finding in the field of multiferroics is that the characteristic magnetic feature at such low temperatures moves towards higher temperatures in the presence of a magnetic-field (H), whereas the corresponding dielectric feature shifts towards lower temperatures with H, unlike the situation near T_N. This observation indicates that the alignment of spins by external magnetic fields tends to inhibit glassy-like slow electric-dipole dynamics, at least in this system, possibly arising from peculiarities in the magnetic structure.