Contacts
communication [at] ens-paris-saclay.fr (communication)

Current Advances in Spinterface and Spin Transport in Organic Spin Valves

Professor Tho NGUYEN, Physics and Astronomy Department, University of Georgia, Athens, Georgia 30602, USA), invited by Quatum and Photonics Molecular Laboratory and Physics Department, ENS Paris-Saclay, will give a lecture about "Current Advances in Spinterface and Spin Transport in Organic Spin Valves".
D'Alembert building, Amphi 112
Add to my Calendar07/16/2018 11:00am 07/16/2018 12:30pm Current Advances in Spinterface and Spin Transport in Organic Spin Valves D'Alembert building, Amphi 112 Europe/Paris public

Organic spin valves (OSVs), which are comprised of an organic spacer sandwiched between two ferromagnetic (FM) electrodes, have attracted great attention from scientific community in the past 16 years [1,2].

Such spin valve structure using inorganic materials has revolutionized magnetic memory and sensor applications. Magnetoresistance (MR) response in OSVs generally relies on the spin injection/detection at the FM/organic interface (dubbed spinterface), and spin diffusion length in the organic spacer.

Organic semiconductors (OSEC) possess weak hyperfine interaction and spin-orbit coupling, and hence long spin lifetime [2]. The reason is that the spin transport is due to π-orbital electrons in OSECs which are consisted of light-weight elements such as hydrogen and carbon.

Therefore, they have been thought to possess considerably long spin diffusion length, suitable for obtaining larger MR in OSVs. However, in conventional OSVs, the interface between the organic and FM electrodes, and the structural order of the organic interlayer are poorly controlled because epitaxial growth is not possible for OSECs.

Spinterface effect and spin transport

Therefore, the spinterface effect and spin transport in these devices are complicated, and their complete understanding has remained elusive [2]. In this talk, I will discuss the current advanced studies in our group for understanding and manipulating the spinterface effect and spin transport in OSVs. In particular, for the spin transport, we will show the statistical origin of the hyperfine interaction strength [3] and the existence of curvature induced spin-orbit coupling [4] in OSECs.

For the spin injection/detection, I will show several methods to manipulate the spinterface effect. These include the use of self-assembled monolayers (SAM) at the interface [5], an organic ferroelectric insulator for the spacer [6], and organic/FM/organic triple layers for the spacer [7].

References

1 Xiong  et al. Nature 427, 821-824 (2004).
2 J. Devkota et al. Adv. Funct. Mater. DOI: 10.1002/adfm.201504209 (2016)
3 Geng et al. Phys. Rev. Letts (under review 2017)
4 Geng et al. Scientific Reports 6, 19461 (2016)
5 Geng et al. Adv. Funct. Mater. 26, 3999-4006 (2016)
6 Subedi  et al. Appl. Phys. Letts 110 (5), 053302 (2017)
7 Liang et al. Organic Electronics 26,314-318 (2015)