Nanoscale Ferroelastic Twins Formed in Strained LaCoO3 Films
Er-Jia Guo, Ryan Desautels, David Keavney, Manuel A. Roldan, Brian J. Kirby, Dongkyu Lee, Zhaoliang Liao, Timothy Charlton, Andreas Herklotz, T. Zac Ward, Michael R. Fitzsimmons, Ho Nyung Lee
The formation of twinning domains has been established as a major mechanism to accommodate epitaxial strain in rhombohedral ferroelastic oxide thin films. The elastic energy can be released at the expense of high interfacial energy at the domain boundaries. The domain orientation in ferroelastic films is expected to be largely influenced by the epitaxy to crystallographically different substrates. Here we report the observation of one-dimensional ferroelastic domains in lanthanum cobaltite thin films. A unidirectional structural modulation is achieved by selective choice of substrates possessing broken in-plane rotational symmetry. This unique structural distortion perturbs the crystal field energy, leading to unexpected inplane anisotropy of orbital configuration and magnetization. These findings demonstrate the utilization of the uniaxial structural variation to control the coupling between spin, lattice, and orbital degrees of freedom in complex ferroic oxides, and reveal the potential for simulation of exotic phenomena in other ferroelastic materials through artificial domain engineering.