Localized Control of Curie Temperature in Perovskite Oxide Film by Capping-Layer-Induced Octahedral Distortion

Abstract

With reduced dimensionality, it is often easier to modify the properties of ultrathin films than their bulk counterparts. Strain engineering, usually achieved by choosing appropriate substrates, has been proven effective in controlling the properties of perovskite oxide films. An emerging alternative route for developing new multifunctional perovskite is by modification of the oxygen octahedral structure. Here we report the control of structural oxygen octahedral rotation in ultrathin perovskite SrRuO_{3} films by the deposition of a SrTiO_{3} capping layer, which can be lithographically patterned to achieve local control. Using a scanning Sagnac magnetic microscope, we show an increase in the Curie temperature of SrRuO_{3} due to the suppression octahedral rotations revealed by the synchrotron x-ray diffraction. This capping-layer-based technique may open new possibilities for developing functional oxide materials.

Abrupt orthorhombic relaxation in compressively strained ultrathin SrRuO3 films

“…We also observed a reduced tilt of a few layers' octahedra at the top of the SRO film where we have capped with STO, to protect the surface. The capping with STO also suppresses the tilt distortions in agreement with earlier studies [23].…”

“…However, for ultrathin films, surface effects can significantly affect the observed properties [22]. Capping with such as STO layer to protect the surface can suppress the octahedral tilts/rotations of the underlying film [23], thus bringing extrinsic effects to the system.…”

Metal-to-Insulator Transition in Ultrathin Manganite Heterostructures

“…This similarity may also suggest that the dead layer has a common origin. Similar to the capping effect on LSMO [39,40], the surface capping has been found to decrease the dead layer thickness of both LNO [78] and SRO [82]. The capping layer plays a role in reducing the surface structure distortion [78].…”

Ferromagnetism and Conductivity in Atomically Thin SrRuO3

“…According to that proposal, the octahedral structure of the atomically thin SrRuO 3 is stabilized by structural coupling to the SrTiO 3 [36]. Recent experiments indeed show an enhancement of the T C by capping the SrRuO 3 with SrTiO 3 [38]. To test whether one-unit-cellthick SrRuO 3 is indeed magnetic and conducting if embedded with SrTiO 3 in a heterostructure, we fabricate high-quality ðSrRuO 3 Þ 1 − ðSrTiO 3 Þ 5 superlattices and single-unit-cell-thick SrRuO 3 samples that are capped with SrTiO 3 .…”