Creating multiferroic and conductive domain walls in common ferroelastic compounds

Abstract

Domain walls in ferroelectrics and ferroelastics often present peculiar functional properties, offering an intriguing route toward the design of nano-devices. Here we use first-principles simulations to illustrate an approach for engineering such walls, working with representative ferroelastic perovskites LaGaO 3 and CaTiO 3 (insulating, non-magnetic, non-polar). We show that a wide range of substitutional dopants can be used to create long-range-ordered structures confined within the walls of these compounds, yielding functional interfaces with tailor-made properties. We thus identify clear-cut strategies to produce metallic walls within an insulating matrix. Further, we find ways to create magnetic walls that also display ferroelectric order (proper or improper), thus providing an original route to obtain magnetoelectric multiferroics. Given the recent developments on the preparation of high-density domain structures in perovskite films, our results suggest a definite path toward new functional nano-materials.

Crackling noise and avalanches in minerals

“…First, we know almost nothing about the detailed structure of boundaries between growth twins and research in this field has hardly started. Boundaries between ferroelastic twins, on the other hand, are much better understood (Janovec et al 1994;George et al 2003;Schiaffino and Stengel 2017;Casals et al 2018;Royo and Stengel 2019;Warwick et al 2019;Zhao and Iniguez 2019) and virtually all previous work relates to ferroelastic materials (Salje 2012). The main result of ferroelastic twin walls is that two twins do not just join in the boundary without topological defects but that they generate a thin layer of materials which has a different crystal structure from the bulk material.…”

Phase‐Field Study of Nanocavity‐Assisted Mechanical Switching in PbTiO3 Thin Films

“…Phase‐field simulations have become a commonly employed approach for acquiring a deeper understanding of the mechanics dictating polarization dynamics in ferroelectric materials. [ 27–30 ] Multiple phase‐field endeavors have been undertaken to clarify the fundamental phenomena related to mechanical switching processes. [ 16,20,23,25,31–40 ] Regarding mechanical domain control in thick films, these studies have substantially contributed to advancing our understanding of the energetic mechanisms that promote the stability of polarization reversal across significant film thicknesses.…”

Compressive Property and Toughening Mechanism of Directionally Solidified Fe(Al, Ta)/Fe2Ta (Al) Eutectic Composites

“…However, the severe room‐temperature brittleness leads to its undesirable application in industrial production. [ 1–4 ] At present, the improvement of materials often starts from the relationship between “composition–processing–microstructure–performance.” [ 5 ] Alloying has long been confirmed to improve the strength, toughness, and corrosion resistance of Fe–Al‐based alloys. [ 6,7 ] Hardening alloy elements, for example, V, Ti, Cr, Ta, etc., can be used to solve its room‐temperature brittleness defects.…”