Laser stimulated THz emission from Pt/CoO/FeCoB

Abstract

The antiferromagnetic order can mediate a transmission of the spin angular momentum flow, or the spin current, in the form of propagating magnons. In this work, we perform laser stimulated THz emission measurements on Pt/CoO/FeCoB multilayers to investigate the spin current transmission through CoO, an antiferromagnetic insulator, on a picosecond timescale. The results reveal a spin current transmission through CoO with the diffusion length of 3.0 nm. In addition, rotation of the polarization of the emitted THz radiation was observed, suggesting an interaction between the propagating THz magnons and the Néel vector in CoO. Our results not only demonstrate the picosecond magnon spin current transmission but also the picosecond interaction of the THz magnons with the Néel vector in the antiferromagnet.

Temperature‐Dependent Terahertz Emission from Co/Mn2Au Spintronic Bilayers

“…Our observation is basically consistent with recent reports on the temperature dependence of spin Hall resistivity of Pt layer. [ 57,59 ] We also would like to mention that with decreasing the temperature, the exchange coupling of FM/Mn 2 Au bilayer builds up, which was observed by an asymmetric shape of the hysteresis loops at low temperature. [ 52 ] A small modulation of the exchange‐coupling strength at the interface between FM and AFM might lead to notable changes in magnetic properties.…”

Different spin relaxation property observed in linearly and circularly polarized laser induced terahertz emission from Bi/Co bilayer

“…The pump laser was focused on the film with a fluence of 0.62 mJ/cm 2 . The polarization of the THz wave emitted from the sample surface was analyzed with two wire grids [27,33]. We measured the emitted THz wave using the electro-optic (EO) sampling method [34] with a 1-mm-thick ZnTe(110) crystal.…”

“…The THz emission experiment conducted with structures widely used in spintronics THz emitters [23][24][25], e.g., ferromagnet/Bi bilayers, has not been reported so far. When a femtosecond laser pulse is irradiated on the ferromagnet/Bi bilayer, spin current can be generated by the ultrafast demagnetization of the ferromagnetic layer due to the conservation of angular momentum [26][27][28][29]. Then, the THz wave can be emitted owing to spintransport and spin-charge conversion in the Bi layer.…”

Magnetization Precession at Sub‐Terahertz Frequencies in Polycrystalline Cu2Sb‐Type (Mn–Cr)AlGe Ultrathin Films

“…The terahertz (THz) frequency range from 0.1 to 10 THz between the microwave band and the mid‐infrared band in the electromagnetic spectrum is often referred to as the “THz gap.” The THz frequency range is intended to be used for biological diagnosis, [ 1 ] objective imaging, [ 2,3 ] and next‐generation (6G) wireless communication networks. [ 4,5 ] Recently, developments of new spintronic applications in the THz frequency range have been investigated for spintronic THz emitter, [ 6–8 ] ultrafast spin current, [ 9–11 ] antiferromagnetic materials, [ 12–14 ] and ferromagnetic metal films with large perpendicular magnetic anisotropy (PMA). [ 15–18 ] This newly developed high‐speed spintronic technology, THz spintronics, [ 19,20 ] holds promise for the future Internet of Things society.…”

“…

frequency range is intended to be used for biological diagnosis, [1] objective imaging, [2,3] and next-generation (6G) wireless communication networks. [4,5] Recently, developments of new spintronic applications in the THz frequency range have been investigated for spintronic THz emitter, [6][7][8] ultrafast spin current, [9][10][11] antiferromagnetic materials, [12][13][14] and ferromagnetic metal films with large perpendicular magnetic anisotropy (PMA). [15][16][17][18] This newly developed high-speed spintronic technology, THz spintronics, [19,20] holds promise for the future Internet of Things society.A leading device in the field of spintronics is nonvolatile magnetoresistive random access memory (MRAM).

…”