| AVS 64th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures Division | Tuesday Sessions |
| Session MI+2D+AC+NS-TuA |
| Session: | Spin-Orbit Phenomena at Surfaces and Interfaces |
| Presenter: | Alexandra Steffen, Oak Ridge National Laboratory |
| Authors: | A.C. Steffen, Oak Ridge National Laboratory N. Herath, Oak Ridge National Laboratory J. Keum, Oak Ridge National Laboratory H. Zhang, Oak Ridge National Laboratory K. Hong, Oak Ridge National Laboratory J. Jakowski, Oak Ridge National Laboratory J. Huang, Oak Ridge National Laboratory J. Browning, Oak Ridge National Laboratory C.M. Rouleau, Oak Ridge National Laboratory I.N. Ivanov, Oak Ridge National Laboratory V. Lauter, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Spin-dependent phenomena, such as the extended spin relaxation time and spin diffusion length due to the very week spin-orbit coupling found in organic spin valves (OSV), are of interest from the view of both fundamental research and development of low power spintronic devices.
While deuteration is widely used for contrast variation measurements under the assumption that the deuterated structure shows identical characteristics in comparison to the protonated version, recently, strong isotopic effect on optoelectronic properties was reported and a remarkable reduction in the open circuit voltage was found [1].
In OSV systems, the interfacial properties are crucial for the understanding of the origin of the macroscopic properties. Still, to identify the exact behavior of the interfaces remains challenging, especially for buried soft matter/hard matter interfaces. Here, we utilize via Polarized Neutron Reflectometry to study depth-resolved the magnetic and chemical structure.
Our system under investigation are prototype spintronic devices with LSMO/polymer/Co trilayer structure, where polyfluorene (PFO) is selected as an optimal ‘hole’ conducting polymer through the model pre-screening based on the electron affinity and electron’s effective mass values obtained from theoretical calculations. Using the exceptional syntheses and deuteration capabilities we have recently completed syntheses of four PFO isotopes, i.e., protonated (P), main-chain deuterated (MD), side-chain deuterated (SD) and fully deuterated (FD) PFOs. By creating such modified polymers, the subatomic, intermolecular and interfacial interactions are modified and characteristics like the π-π interaction become tunable. For neutron scattering experiments, the nuclear cross-section varies with the isotopic substitution, thus via changing the contrast with chain-specific deuteration, different parts of a sample are investigated individually.
While our main goal is the understanding the effect of deuterium substitution on the spin-dependent electron transport, in this presentation, we will focus on the details of the structural and magnetization profiles on both LSMO\polymer and polymer\Co interfaces and their impact on the coupling between magnetic layers. We will present the results obtained via Polarized Neutron Reflectometry and discuss the interpretation of the depth-resolved magnetometry study.
[ 1 ] Ming Shao et al., The isotopic effects of deuteration on optoelectronic properties of conducting polymers. Nature Communications, 5:3180, January 2014.