Spin Pump and Probe in Lanthanum Strontium Manganite/Platinum Bilayers
G. Y. Luo1,2, J. G. Lin2*, Wen-Chung Chiang3, Ching-Ray Chang1
1Department of Physics, National Taiwan University, Taipei, Taiwan
2Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
3Department of Optoelectric Physics, Chinese Culture University, Taipei, Taiwan
* presenting author:Jauyn Grace Lin, email:jglin@ntu.edu.tw
Ferromagnetic resonance driven spin pumping (FMR-SP) is a novel method to transfer spin torque from the ferromagnetic (FM) layer into the adjacent normal metal (NM) layer in an FM/NM bilayer system. Simultaneously, the spin current can be probed in NM layer via inverse spin Hall effect (ISHE) owing to the spin-orbital interaction. Concerning the ISHE effect, in spite of numerous FM/Pt bilayers have been investigated, lanthanum strontium manganite(LSMO)/Pt system has rarely been studied. In this work, the technique of FMR-SP has been applied on two series of LSMO/Pt bilayers with the thickness of each layer being varied. It is found that the obtained values of spin mixing conductance and spin Hall angle of LSMO/Pt bilayers are very close to those of permalloy(Py)/Pt regardless the electronic properties of LSMO being very different from Py. In addition, a better fit with spin backflow model for the data of spin current vs. Pt thickness yields an enhancement of spin Hall angle by three times, demonstrating the essential role of spin current back flow at interface.

Keywords: Ferromagnetic resonance, spin pumping, spin current, LSMO