Interfacial composition in charge ordered-based tunnel junctions
EMSL Project ID
47525
Abstract
The goal of this rapid access proposal is to use laser-assisted atom probe tomography (APT) to investigate the compositional depth profile and interfacial integrity of all-oxide tunnel junctions, in which the barrier layer is a compound that exhibits a charge ordered ground state. As part of a 5 PI ONR-funded project aimed at developing charge-ordering based transistors, our group is working to develop transistors based on charge-ordering phase transitions. Our most promising device design involves utilizing a charge ordered layer as a tunnel barrier between two conducting oxide electrodes. At Drexel, we have begun an extensive investigation of these charge ordered tunnel junctions. While our current approach combines high resolution transmission electron microscopy (TEM), x-ray reflectivity (Fig. 1), and electronic transport measurements, our research effort would be substantially enhanced by applying APT to these trilayers to better understand interfacial composition and intermixing. In particular, we propose to use the APT system to quantify the structure of La0.7Sr0.3MnO3 / La0.33Sr0.67FeO3 interfaces in a five layer sample (Fig. 1) grown on SrTiO3. This sample consists of two tunnel barriers to allow us to gain more information from a single sample; the La0.7Sr0.3MnO3 (LSMO) layers act as metallic electrodes, while the charge-ordered La0.7Sr0.3FeO3 (LSFO) layers are the tunnel barriers. The thickness of the LSMO layers is ~16 nm, while the LSFO layer is ~4 nm. The fabrication steps needed to obtain APT specimens from the thin films will be performed at PNNL. Following the APT measurements, we will analyze the data to identify the degree of cation intermixing as the LSMO/LSFO interfaces and to quantify the cation compositions through the sample.
Project Details
Project type
Limited Scope
Start Date
2012-09-04
End Date
2012-10-26
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members