Tunnel Conduction in Epitaxial Bilayers of Ferromagnetic LaCoO₃/La_2/3Sr_1/3MnO₃ Deposited by a Chemical Solution Method

Abstract

We report magnetic and electronic transport measurements across epitaxial bilayers of ferromagnetic insulator LaCoO3 and half-metallic ferromagnet La2/3Sr1/3MnO3 (LCO/LSMO: 3.5 nm/20 nm) fabricated by a chemical solution method. The I-V curves at room temperature and 4K measured with conducting atomic force microscopy (CAFM) on well-defined patterned areas exhibit the typical features of a tunneling process. The curves have been fitted to the Simmons model to determine the height (φ) and width (s) of the insulating LCO barrier. The results yield φ = 0.40 ± 0.05 eV (0.50 ± 0.01 eV) at room temperature (4K) and s = 3 nm, in good agreement with the structural analysis. Our results demonstrate that this chemical method is able to produce epitaxial heterostructures with the quality required for this type of fundamental studies and applications.

Polymer assisted deposition of epitaxial oxide thin films

“…Jain et al 107 2) the height of the barrier, E=0.4 eV. 108 The latter value was very close to the obtained in barriers of STO deposited by PLD 110 , demonstrating that ultra-thin layers of LCO prepared by PAD retained a good insulator character and can be used as tunneling barriers in combination with LSMO at room temperature.…”

Epitaxial La0.7Sr0.3MnO3thin films on silicon with excellent magnetic and electric properties by combining physical and chemical methods

“…Among CSD techniques, we selected polymerassisted deposition (PAD) [31][32][33] because it is one of the most suitable processes to produce high-quality epitaxial complex and multilayer structured films [34]. In particular, high-quality epitaxial LSMO thin films were synthetized on single crystal-substrates by PAD [35,36] with a perfect control of the thickness [37] to prepare multilayers controlling their magnetoresistive response [38] and tunnel junctions [39]. PAD is a softchemistry technique that uses branched polymers to coordinate and stabilize different cations in an aqueous solution, which is therefore homogeneously spin-coated on a substrate [40].…”

Room-Temperature Ferromagnetism in Thin Films of LaMnO3 Deposited by a Chemical Method Over Large Areas

“…7 In an important step forward in this direction, some of us recently demonstrated the possibility of fabricating heteroepitaxial bilayers and functional tunnel junctions by a polymer assisted chemical deposition method (PAD). 8,9 This chemical method, originally introduced by Jia et al, 10 was successfully applied to grow complex oxide films, 11,12,13 nitrides, 14,15 and carbides. 16 In this paper we address the PAD synthesis of high quality epitaxial thin films of LaMnO3, over large areas.…”