Tailoring the domain structure of epitaxial BiFeO3 thin films

Control of the ferroelastic and ferroelectric domain structure of BiFeO3 through the use of epitaxial growth on substrates with reduced symmetry is reviewed. The first approach presented utilizes orthoscandate substrates, specifically TbScO3, to reduce the number of possible ferroelastic domains from 4 to 2. Experimental results and phase field simulations are presented which are in agreement with the theory of anisotropic strain relaxation, due to differing in-plane lattice parameters of the orthorhombic substrate, causing a reduction in the possible domains. The second approach that is presented involves the use of miscut cubic substrates, such as SrTiO3, to tailor the domain structure from 4-domain to 2- or single-domain is presented, the former being achieved with a miscut in the [1 0 0] direction and the latter with a miscut in the [1 1 0] direction, assuming a film normal orientation of [0 0 1]. The use of these techniques in understanding the fundamental nature of the ferroelastic and ferroelectric properties in BiFeO3, and the use of these methods in tailoring BiFeO3 to meet the needs of future device applications is discussed.