TY - GEN
T1 - Terahertz emission from magnetic thin film and patterned heterostructures
AU - Lendinez, Sergi
AU - Li, Yi
AU - Wu, Weipeng
AU - Taghipour Kaffash, Mojtaba
AU - Zhang, Qi
AU - Zhang, Wei
AU - Pearson, John E.
AU - Divan, Ralu
AU - Schaller, Richard D.
AU - Hoffmann, Axel
AU - Wen, Haidan
AU - Jungfleisch, Matthias Benjamin
N1 - Funding Information:
This work was supported by the National Science Foundation under Grant No. 1833000. Thin film deposition was performed at Argonne and supported by the U.S. Department of Energy, Office of Science, Materials Science and Engineering Division. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Publisher Copyright:
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PY - 2019
Y1 - 2019
N2 - In recent years terahertz (THz) technology has been an emerging research field with a broad range of applications. THz radiation falls between the infrared and microwave radiation in the electromagnetic spectrum. Most THz sources to date are not related to the spin degree of freedom; however, recent research efforts in spintronics and ferromagnetism demonstrated that the electron spin offers completely new opportunities for the generation of ultrafast photocurrents. For instance, magnetic heterostructures are very easy to pattern and potentially allow to tailor THz emission characteristics by design. Here, we demonstrate that an ultrafast spin-current pulse driven by a femtosecond laser pulse can create THz transients in microstructured magnetic heterostructures due to the inverse spin Hall effect. We compare the THz electric field and the THz spectrum of a control CoFeBPt film with microstructured CoFeBPt wires as well as microstructured CoFeBMgO wires patterned on an extended Pt film. We find that the THz electric field amplitude is proportional to the coverage of the CoFeBPt heterostructure on top of the MgO substrate. Furthermore, we analyze the magnetization direction dependence of the THz transients with respect to the easy axis of the ferromagnetic wire. The presented results are the first steps towards shaping and controlling the THz properties by microstructuring of spintronics-based THz emitters.
AB - In recent years terahertz (THz) technology has been an emerging research field with a broad range of applications. THz radiation falls between the infrared and microwave radiation in the electromagnetic spectrum. Most THz sources to date are not related to the spin degree of freedom; however, recent research efforts in spintronics and ferromagnetism demonstrated that the electron spin offers completely new opportunities for the generation of ultrafast photocurrents. For instance, magnetic heterostructures are very easy to pattern and potentially allow to tailor THz emission characteristics by design. Here, we demonstrate that an ultrafast spin-current pulse driven by a femtosecond laser pulse can create THz transients in microstructured magnetic heterostructures due to the inverse spin Hall effect. We compare the THz electric field and the THz spectrum of a control CoFeBPt film with microstructured CoFeBPt wires as well as microstructured CoFeBMgO wires patterned on an extended Pt film. We find that the THz electric field amplitude is proportional to the coverage of the CoFeBPt heterostructure on top of the MgO substrate. Furthermore, we analyze the magnetization direction dependence of the THz transients with respect to the easy axis of the ferromagnetic wire. The presented results are the first steps towards shaping and controlling the THz properties by microstructuring of spintronics-based THz emitters.
KW - Magnetic microstructure
KW - Spin Hall effect
KW - Spintronics
KW - Terahertz spintronics
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U2 - 10.1117/12.2526194
DO - 10.1117/12.2526194
M3 - Conference contribution
AN - SCOPUS:85073211690
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Spintronics XII
A2 - Drouhin, Henri-Jean M.
A2 - Wegrowe, Jean-Eric
A2 - Razeghi, Manijeh
A2 - Jaffres, Henri
PB - SPIE
T2 - Spintronics XII 2019
Y2 - 11 August 2019 through 15 August 2019
ER -