Ferromagnetic oxide heterostructures on silicon
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unctional Oxides Research Letter
Ferromagnetic oxide heterostructures on silicon Srinivasa Rao Singamaneni, Materials Science Division, Army Research Office, Research Triangle Park, North Carolina 27709, USA; Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA; Department of Physics, The University of Texas at El Paso, El Paso, Texas 79968, USA J.T. Prater, Materials Science Division, Army Research Office, Research Triangle Park, North Carolina 27709, USA; Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA Fan Wu, Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA; Princeton Institute for the Science and Technology of Materials (PRISM), Princeton University, 70 Prospect Avenue, Princeton, New Jersey 08540, USA J. Narayan, Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA Address all correspondence to S.R. Singamaneni at [email protected] (Received 12 May 2016; accepted 8 July 2016)
Abstract Heterostructures consisting of two ferromagnetic oxides La0.7Ca0.3MnO3 (LCMO) and SrRuO3 (SRO) were epitaxially grown by pulsed laser deposition onto a silicon (Si) substrate buffered by SrTiO3 (STO)/MgO/TiN. The x-ray scans and electron-diffraction patterns reveal the epitaxial nature of all five layers. From transmission electron microscopy, the thicknesses of the LCMO and SRO layers were estimated to be ∼100 and ∼200 nm, respectively. The magnetic properties of individual SRO and LCMO layers are in good agreement with the previous studies reported for those individual layers deposited on lattice-matched substrates, such as STO. The LCMO/SRO heterostructures showed enhanced switching field (from 6008 to 7600 Oe), which may originate from the bulk part of the heterostructure. The ability to grow these multifunctional structures on Si provides a route for wafer scale integration with Si, in contrast to oxide substrates that are not suitable for CMOS integration for microelectronics and spintronics applications.
Introduction Complex oxide heterostructures have generated tremendous research interest[1–3] due to the wealth of new physical properties needed for solid-state devices with novel functionalities unattainable with conventional semiconductor structures. In particular, ferromagnetic oxides, superconductors, multiferroics, and other multifunctional oxide materials offer rich possibilities for exploration of both fundamental physical phenomena and device applications. With the advancements in the growth of epitaxy oxide materials, epitaxial oxide heterostructures are emerging as outstanding candidates for realization of devices in which diverse material properties such as ferromagnetism, ionic conductivity, piezoelectricity, and ferroelectricity can be flexibly coupled to achieve new functionality. However, putting this functionality to work remains a key issue. To date,
