Strain control of multiferroic domains: towards solving the problem of polarisation fatigue in BiFeO3 thin films

We propose a neutron diffraction experiment to investigate substrate control of multiferroic domains in (111)-oriented BiFeO3 films. This is a continuation of a series experiments in which we have shown, contrary to previous reports, that the as-grown structure of (111)-BFO films not a rhombohedral monodomain but in fact consists of a sub-micron texture of monoclinic magneto-structural domains. The presence of these domains results in undesirable effects of polarisation fatigue and electrical breakdown. It has been shown the domain structure in BFO films depends dramatically on mismatch strain, so by measuring films grown on substrates with an order-of-magnitude lower epitaxial strain and with a substrate miscut, we aim to control the properties and populations of the multiferroic domains with the goal of growing a single magnetic and structural monodomain.