Epitaxial Photostriction–Magnetostriction Coupled Self-Assembled Nanostructures

Abstract

Self-assembled vertical nanostructures take advantage of high interface-to-volume ratio and can be used to design new functionalities by the choice of a proper combination of constituents. However, most of the studies to date have emphasized the functional controllability of the nanostructures using external electric or magnetic fields. In this study, to introduce light (or photons) as an external control parameter in a self-assembled nanostructure system, we have successfully synthesized oxide nanostructures with CoFe(2)O(4) nanopillars embedded in a SrRuO(3) matrix. The combination of photostrictive SrRuO(3) and magnetostrictive CoFe(2)O(4) in the intimately assembled nanostructures leads to a light-induced, ultrafast change in magnetization of the CoFe(2)O(4) nanopillars. Our work demonstrates a novel concept on oxide nanostructure design and opens an alternative pathway for the explorations of diverse functionalities in heteroepitaxial self-assembled oxide nanostructures.

New strain states and radical property tuning of metal oxides using a nanocomposite thin film approach

“…1 In these composites, new phenomena also occur giving a very powerful way to tune device functionality. Very high ferroelectric Curie temperatures, 2 strongly improved dielectric tunability, 3 reducing dielectric loss, 4 enhanced multiferroic coupling, 5 photostriction-magnetic coupling, 6 strongly enhanced current densities in superconductors, 7 new kinds of memristor devices, 8 and strongly enhanced ionic conduction at lower temperatures have all been reported. 9,10 However, the understanding and origin of unusual strain states in nanocomposite films have not been explored to date.…”

Materials News: Interfacial chemistry and atomic arrangement of ZrO2 − La2/3Sr1/3MnO3 pillar-matrix structures

“…C In functional oxides such as superconducting cuprates and ferromagnetic manganites, the investigation of electrically insulating columnar oxide defects embedded in the conducting matrix materials has experienced an increasing research activity in the past decade. 1,2 From the fundamental point of view, this activity was initiated by the exploration of the crystalline structure and elemental distribution at the interface between the columnar defects and the matrix material with the subsequent strain-and defect-induced modification of their electronic and magnetic properties. Elemental and electronic reconstructions at the interface between complex oxides with different functionalities are challenging phenomena to be explored.…”

“…3 Research on self-assembled vertically aligned nanocomposite thin films with two immiscible components hetero-epitaxially grown on single crystal substrates represents another branch of these activities. 1,4 These structures have the advantage of utilizing the functionalities of both components with the possibility to tune the material properties by tailoring the interface-to-volume ratio, hetero-epitaxial strain, or modifying the cation valence state. From the application point of view, columnar non-conducting BaZrO 3 or SrZrO 3 defects in superconducting YBa 2 Cu 3 O 7 thin films have been proven to enhance the flux-line pinning properties drastically and are used in several 3rd generation commercial superconducting tape fabrication technologies.…”

Mesocrystal-embedded functional oxide systems

“…In the case of CFO mesocrystal-embedded in SRO matrix reported by Liu et al, the SRO matrix inherently shows a large photostrictive effect, an expansion of lattice under illumination. [23] From the investigation of ultrafast XRD, SRO exhibits a large photon-induced lattice expansion of 0.5%-1.5% under the laser fluence of 3-15 mJ/cm 2 [24][25][26] , implying that the compressive strain of CFO (∼1.2% in SRO matrix) could be fully relaxed under a threshold of laser fluence. This concept was proven by a combination of the magneto-optic Kerr effect (MOKE) measurement and magnetic force microscopy (MFM).…”