Spin-lattice coupling in multiferroic Pb(Fe1/2Nb1/2)O3 thin films

TL;DR

This study investigates the spin-lattice coupling in Pb(Fe1/2Nb1/2)O3 thin films through magnetization and x-ray diffraction, revealing key temperature points and magnetic behaviors relevant to multiferroic properties.

Contribution

The paper provides the first detailed analysis of spin-lattice interactions and magnetic anomalies in epitaxial Pb(Fe1/2Nb1/2)O3 thin films, highlighting the coupling at the Néel temperature.

Findings

Identification of Burns' temperature at ~640 K

Detection of a magnetic anomaly at 200 K

Observation of weak ferromagnetism up to 300 K

Abstract

We have made magnetization and x-ray diffraction measurements on an epitaxial Pb(Fe1/2Nb1/2)O3 200 nm film. From the temperature dependence of the out-of-plane lattice parameter we can assign a Burns' temperature at Td ~ 640 K, a temperature at T* ~ 510 K, related to the appearance of static polar nanoregions, and an anomaly occurring at 200 K. The latter is precisely the N\'eel temperature TN determined from magnetization and points to spin-lattice coupling at TN ~ 200 K. We also observe "weak ferromagnetism" up to 300K and propose superantiferromagnetic clusters as a plausible scenario to explain this hysteresis above TN.