Vertical Strain Engineering of Epitaxial La 2/3 Sr 1/3 MnO 3 Thin Films by Spontaneously Embedding ZrO 2 Nanopillar Arrays

Rational control of local strain distributions and thus the functional properties of epitaxial thin films has been a long‐standing goal in the development of new physics and novel devices based on strain‐sensitive materials. Here, the fabrication of La 2/3 Sr 1/3 MnO 3 (LSMO) films with strain fields arising from vertical epitaxial embedding of ultra‐small ZrO 2 nanopillars, diameter 4.0  ±  0.6 nm, is reported. High quality films are obtained with average distance between adjacent nanopillars of 9.0  ±  0.3 nm for x   = 0.2 in (LSMO) 1− x :(ZrO 2 ) x . The strain distribution of the vertical interface is analyzed in detail and the dominant state of the interfacial strain is verified. Remarkably, with increasing x , the Curie temperature T C and metal–insulator (MI) transition temperature T MI show a surprisingly large depression, revealing the significant tuning capability of the vertical tensile stress originating from the small‐size ZrO 2 pillars. A systematic tunability of the low field magnetoresistance is also found. The field dependence of the magnetization exhibits both horizontal and vertical shifts. The exchange bias field H E increases with increasing x , while magnetization shift M shift is unchanged. The results suggest the possibility of strain tuning through epitaxial nanostructures for multifunctional applications across many fields with appropriate selection of matrix and nanopillar materials.