Spin Pumping measurement in the presence of different degree of Oxidized Aluminium layer sandwich between NiFe and Pt

M. Sanjoy Singh^1,2*, Minn-Tsong Lin^1,3,4

¹Department of Physics, National Taiwan University, Taipei 10617, Taiwan
²Nano Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
³Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
⁴Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan

* Presenter:M. Sanjoy Singh, email:amsanjoy@gmail.com

In spintronics research, Spin Pumping (SP) Technique at Ferromagnetic Resonance (FMR) Condition has been quite successful in exploring the core mechanics of spintronics namely generation, manipulation and detection of spin current in a Ferromagnet (FM) e.g. NiFe/Nonmagnetic (NM) material e.g. Pt. For our study of SP, we prepare samples that has an extra layer of aluminium (Al) which has been oxidized in different controlled times in order to have different degree of oxidized Al layer and sandwich between NiFe and Pt. We are interested in how these different oxidized Al layers affect the spin pumping nature. Our results from analysis of damping constant at FMR shows that the presence of different degree of oxidized Al layer reduces exponentially the transfer of spin current from FM to NM and similar consequences can be expected also for the Inverse Spin Hall Voltage (VISHE). But from our findings in voltage measurement, only in the presence of oxide layer, the voltage is comparable to its pure NiFe/Pt which indicates the presence of different voltage source other than VISHE. The most likely candidate for this voltage source is coming from Spin Rectification Effect (SRE) but more research is required for definitive conclusion.

*This project is financially sponsored by National Science and Technology Council (NSTC 112-2112-M-002-046-MY3)

Keywords: Spin Pumping, Ferromagnetic Resonance, Inverse Spin Hall Voltage, Spin Rectification Effect