Abstract
Laser pulse induced terahertz (THz) emission from Ta//MgO thin films, with varying compositions and annealing temperatures, is investigated. With increasing annealing temperature, the THz emission intensity exhibits significant dependence on , with maxima at of 0.1–0.3. The dependence of the THz emission originated from the composition dependence of the spin currents induced in formed by the crystallization of amorphous CoFeB after the annealing. The origin of the laser-induced spin current is qualitatively discussed in terms of a ballistic transport of hot electrons and a spin-dependent Seebeck effect with different compositions.
- Received 25 June 2019
- Revised 17 September 2019
DOI:https://doi.org/10.1103/PhysRevB.100.140406
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