Title: Spinterface-spin injection and spin detection via organic semiconductor and ferromagnet hybrid interfaces

Guest Speaker: Kai Wang (University of Twente, Enschede, the Netherlands)

Time: 2014-12-24 (Wednesday), 10:00-11:30 
Location: Conference Room, Institute of Optoelectronic Technology

Abstract

To introduce an organic semiconductor (i.e., OSC) in spintronics has triggered a number of  studies  into  electronic  and  magnetic  properties  of  OSC-ferromagnet  hybrid  interfaces,  and organic spintronic memory devices. The pure carbon (i.e., C) form, buckminsterfullerene (i.e., C60), has been considered as an excellent candidate for spin transport and manipulation due to long  spin  lifetime,  very  weak  spin-orbit  coupling  (i.e.,  SOC)  and  absence  of  hyperfine interaction (i.e., absence of hydrogen atoms). It is crucially important to properly engineer the hybrid interfaces in order to achieve highly efficient spin injection  [1]. In this talk,  apart from a  brief  review  of  current  progress  of  organic spintronics,  three  vertical  organic  spintronic devices I.  sapphire/Co/AlOx/Al/Cu;II.  sapphire/Co/AlOx/C60/Al/Cu;III.sapphire/Co/C60/AlOx/Al/Cu will  be  introduced  in  order  to  investigate  such  interfacial  hybridization  phenomena.  The tunneling  mechanism  is  mainly  governed  by  tunneling  anisotropic  magnetoresistance (TAMR)  [2,3]. Such effect is ascribed to the modulation of the density of states (DOS) when the magnetization is applied along different crystallographic direction of the epitaxial Co thin film. In addition to this, I will also address the importance of characterizing such hybrid states by  X-ray  absorption  spectroscopy  (XPS)  and  X-ray  magnetic  circular  dichroism  (XMCD) methods [4].
References:
1.  S. Sanvito, Nat. Phys. 6, 562 (2010).
2.  K. Wang, et al., Phys. Rev. B 88, 034407 (2013).
3.  K. Wang, et al., Phys. Rev. B 89, 174419 (2014).
4.  P. K. J. Wong, et al., J. Mater. Chem. C 1, 1197 (2013).

Biography

NanoElectronics  Group,  MESA+  Institute  for  Nanotechnology,  University  of  Twente,  P.O. Box 217, Enschede, 7500AE, the Netherlands.

2004-2008  Bachelor  of  Technology  (BTech),  Optoelectroncis,  Macquarie  University,  Sydney, Australia.
2008-2009  Honors degree, Optoelectronics, Macquarie University, Sydney Australia.
2009-2011  Master of Philosophy (MPhil), Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
2011-Present  Doctor  of  Philosophy  (PhD)  candidate,  Applied  Physics,  University  of  Twente, Enschede, the Netherlands.