Laser-induced terahertz (THz) emission in Ta/CoFeB/MgO films with various thicknesses of CoFeB and for various annealing temperatures was studied. The THz emission intensity exhibited its maximum value for a CoFeB layer thickness of approximately 1.0 nm, and this maximum value was enhanced by 1.5 times by annealing at 300 °C. A correlation was found in the annealing dependence between saturation magnetization, conductivity, and THz emission intensity. The origin of the enhancement of THz emission intensity due to annealing was discussed in terms of the increase in the mean free path of majority spin hot electrons in the CoFeB layer with crystallization due to the annealing.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)