Direct detection of pure AC spin-current by x-ray pump-probe measurements
J. X. Deng
P. S. Keatley
G. van der Laan
Z. Q. Qiu
Physical Review Letters
American Physical Society
This is the author accepted manuscript. The final version is available from the American Physical Society via the DOI in this record.
Despite recent progress in spin-current research, the detection of spin current has mostly remained indirect. By synchronizing a microwave waveform with synchrotron x-ray pulses, we use the ferromagnetic resonance of the Py (Ni81Fe19) layer in a Py/Cu/Cu75Mn25/Cu/Co multilayer to pump a pure AC spin current into the Cu75Mn25 and Co layers, and then directly probe the spin current within the Cu75Mn25 layer and the spin dynamics of the Co layer by x-ray magnetic circular dichroism. This element-resolved pump-probe measurement unambiguously identifies the AC spin current in the Cu75Mn25 layer.
We acknowledge helpful discussion with Arne Brataas. Financial support from National Science Foundation DMR-1504568 NRF through the Global Research Laboratory project of Korea is gratefully acknowledged. The Advanced Light Source is supported by the US Department of Energy under contract number DE-AC02-05CH11231. JD acknowledges fellowship support from the China Scholarship Council and National Science Foundation of China under Grant Nos. 51331006. LRS, PSK, and RJH acknowledge the support of the Engineering and Physical Sciences Research Council (EPSRC) through grants EP/J018767/1 and EP/I038470/1. GvdL acknowledges support of the EPSRC through grant EP/J018767/1.
Physical Review Letters, 2016, 117, 076602