Measuring terahertz radiation from Ni and its heterojunction thin films by femtosecond laser
Ni film,Ni/Pt bilayer and CoFeB/Ni bilayer heterojunction with a thickness of 10 nm were grown on SiO2 substrates by magnetron sputtering,and their terahertz emission spectra excited by femtosecond laser technology were measured.Through spectral analysis,it was found that the ter-ahertz radiation of these three kinds of Ni films mainly came from the ultrafast spin-to-charge conver-sion,and the conversion mechanism was different for different structures.For single-layer Ni films,terahertz radiation was mainly due to the ultrafast demagnetization of Ni and the anomalous Hall effect.For the Ni/Pt bilayer,Ni played the role of spin injection,and the Pt completed the spin-to-charge conversion to generate a terahertz signal.For CoFeB/Ni bilayer,the spin current was genera-ted by CoFeB,and Ni played the role of spin-to-charge conversion.The magnetic properties of ferro-magnetic Ni materials could be studied by the femtosecond laser-terahertz technology.
Ni nanofilmsheterojunction nanofilmsfemtosecond laser technologyterahertz e-mission spectraspin-to-charge conversion
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