講演情報
[15p-PB1-9]Spintronic terahertz emission from Fe/Pt multilayers
〇(BC)Takumi Nakazono1, Shinji Isogami2, Yuta Sasaki2, Yukiko Takahashi2, Takuya Satoh1, Kihiro Yamada1 (1.Science Tokyo, 2.NIMS)
キーワード：
spin current、terahertz radiation、ultrafast spectroscopy
The dissipation of spin angular momentum during ultrafast demagnetization generates a picosecond-wide spin-current pulse. When this spin-current pulse flows into an adjacent nonmagnetic layer, it is immediately converted into an electric current, resulting in the emission of terahertz (THz) electromagnetic waves via the electric dipole radiation process. Consequently, the emitted THz waveforms provide insight into demagnetization dynamics and spin transport phenomena on ultrashort time scales.
In this study, we investigate these ultrafast properties in Fe/Pt multilayers using THz emission spectroscopy. Three types of Fe/Pt multilayer with a fixed total thickness were prepared on glass substrates: [Fe(3 nm)/Pt(3 nm)]2, [Fe(2 nm)/Pt(2 nm)]3, and [Fe(1 nm)/Pt(1 nm)]6. The emitted THz electromagnetic waves were measured using a standard electro-optic sampling technique when the multilayers were excited by 100-fs laser pulses from a Ti:sapphire oscillator operating at a repetition rate of 80 MHz. The emission amplitude decreases with increasing number of layers. Furthermore, even in the low-fluence regime, a non-monotonic increase in the emission amplitude is observed as a function of excitation fluence. In the presentation, we will provide further experimental details and discuss the origin of the observed behavior.
In this study, we investigate these ultrafast properties in Fe/Pt multilayers using THz emission spectroscopy. Three types of Fe/Pt multilayer with a fixed total thickness were prepared on glass substrates: [Fe(3 nm)/Pt(3 nm)]2, [Fe(2 nm)/Pt(2 nm)]3, and [Fe(1 nm)/Pt(1 nm)]6. The emitted THz electromagnetic waves were measured using a standard electro-optic sampling technique when the multilayers were excited by 100-fs laser pulses from a Ti:sapphire oscillator operating at a repetition rate of 80 MHz. The emission amplitude decreases with increasing number of layers. Furthermore, even in the low-fluence regime, a non-monotonic increase in the emission amplitude is observed as a function of excitation fluence. In the presentation, we will provide further experimental details and discuss the origin of the observed behavior.