Structural Anomalies at the Magnetic and Ferroelectric Transitions in $RMn_2O_5$ (R=Tb, Dy, Ho)

TL;DR

This study investigates the thermal, magnetic, and ferroelectric anomalies in multiferroic $RMn_2O_5$ compounds, revealing strong spin-lattice coupling and magnetic origins of ferroelectricity through experimental data.

Contribution

It provides new experimental evidence linking thermal expansion anomalies with magnetic and ferroelectric transitions in $RMn_2O_5$, highlighting the role of spin-lattice interactions.

Findings

Anomalies in thermal expansion at phase transitions

Correlation between thermal, magnetic, and dielectric anomalies

Neutron scattering indicates spin reorientation in $HoMn_2O_5$

Abstract

Strong anomalies of the thermal expansion coefficients at the magnetic and ferroelectric transitions have been detected in multiferroic $RMn_2O_5$. Their correlation with anomalies of the specific heat and the dielectric constant is discussed. The results provide evidence for the magnetic origin of the ferroelectricity mediated by strong spin-lattice coupling in the compounds. Neutron scattering data for $HoMn_2O_5$ indicate a spin reorientation at the two low-temperature phase transitions.