Open AccessLayer thickness dependence of the terahertz emission based on spin current in ferromagnetic heterostructures
Author(s) -
Hongsong Qiu,
Koji Kato,
K. Hirota,
Nobuhiko Sarukura,
Masashi Yoshimura,
Makoto Nakajima
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.015247
Subject(s) - terahertz radiation , heterojunction , spin hall effect , common emitter , materials science , femtosecond , ferromagnetism , spin (aerodynamics) , condensed matter physics , optics , terahertz time domain spectroscopy , optoelectronics , terahertz spectroscopy and technology , spin polarization , laser , physics , electron , quantum mechanics , thermodynamics
The emission with a bandwidth of 1.5 terahertz based on the spin current in the ferromagnetic heterostructure Co/Pt is demonstrated. The spin transient launched by the NIR femtosecond laser pulse in the Co/Pt is converted into the in-plane charge current due to the inverse spin Hall effect, which gives rise to the terahertz emission towards free space. The dependence of the terahertz emission on the Pt-layer thickness is investigated. To optimize the geometry structure of the new type of emitter, we developed the theoretical model by carefully analyzing the spin transport. Our model reveals the importance to take into account the interfacial spin loss. It can be used to analyze more complex heterostructures.