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Abstract Reducing the switching energy of ferroelectric thin films remains an important goal in the pursuit of ultralow-power ferroelectric memory and logic devices. Here, we elucidate the fundamental role of lattice dynamics in ferroelectric switching by studying both freestanding bismuth ferrite (BiFeO 3 ) membranes and films clamped to a substrate. We observe a distinct evolution of the ferroelectric domain pattern, from striped, 71° ferroelastic domains (spacing of ~100 nm) in clamped BiFeO 3 films, to large (10’s of micrometers) 180° domains in freestanding films. By removing the constraints imposed by mechanical clamping from the substrate, we can realize a ~40% reduction of the switching voltage and a consequent ~60% improvement in the switching speed. Our findings highlight the importance of a dynamic clamping process occurring during switching, which impacts strain, ferroelectric, and ferrodistortive order parameters and plays a critical role in setting the energetics and dynamics of ferroelectric switching. 

The AA′-stacked FCGT is a new class of room-temperature Néel-type skyrmion hosting material with C 6v symmetry. 

The rapid development of computing applications demands novel low‐energy consumption devices for information processing. Among various candidates, magnetoelectric heterostructures hold promise for meeting the required voltage and power goals. Here, a route to low‐voltage control of magnetism in 30 nm Fe_0.5Rh_0.5/100 nm 0.68PbMg_1/3Nb_2/3O₃‐0.32PbTiO₃(PMN‐PT) heterostructures is demonstrated wherein the magnetoelectric coupling is achieved via strain‐induced changes in the Fe_0.5Rh_0.5mediated by voltages applied to the PMN‐PT. We describe approaches to achieve high‐quality, epitaxial growth of Fe_0.5Rh_0.5on the PMN‐PT films and, a methodology to probe and quantify magnetoelectric coupling in small thin‐film devices via studies of the anomalous Hall effect. By comparing the spin‐flop field change induced by temperature and external voltage, the magnetoelectric coupling coefficient is estimated to reach ≈7 × 10⁻⁸ s m⁻¹at 325 K while applying a −0.75 V bias.