Research ArticleSPINTRONICS

Giant nonreciprocal emission of spin waves in Ta/Py bilayers

See allHide authors and affiliations

Science Advances  01 Jul 2016:
Vol. 2, no. 7, e1501892
DOI: 10.1126/sciadv.1501892


Spin waves are propagating disturbances in the magnetization of magnetic materials. One of their interesting properties is nonreciprocity, exhibiting that their amplitude depends on the magnetization direction. Nonreciprocity in spin waves is of great interest in both fundamental science and applications because it offers an extra knob to control the flow of waves for the technological fields of logics and switch applications. We show a high nonreciprocity in spin waves from Ta/Py bilayer systems with out-of-plane magnetic fields. The nonreciprocity depends on the thickness of Ta underlayer, which is found to induce an interfacial anisotropy. The origin of observed high nonreciprocity is twofold: different polarities of the in-plane magnetization due to different angles of canted out-of-plane anisotropy and the spin pumping effect at the Ta/Py interface. Our findings provide an opportunity to engineer highly efficient, nonreciprocal spin wave–based applications, such as nonreciprocal microwave devices, magnonic logic gates, and information transports.

  • Spin waves
  • magnetization dynamics
  • nonreciprocity
  • permalloy
  • spin pumping
  • anisotropy
  • micromagnetics

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

View Full Text

Stay Connected to Science Advances