TY - JOUR
T1 - Magnetic precession modes with enhanced frequency and intensity in hard/NM/soft perpendicular magnetic films
AU - Wu, Guanjie
AU - Zhu, Weihua
AU - Zhu, Zhendong
AU - Xue, Hongwei
AU - Ren, Yang
AU - Liu, Yaowen
AU - Jin, Q. Y.
AU - Zhang, Zongzhi
N1 - Publisher Copyright:
© 2019 the Owner Societies.
PY - 2019
Y1 - 2019
N2 - High frequency magnetic precessions with strong intensity are strongly desired in material systems for high performance magnetic memory or nano-oscillator applications with ultrafast manipulation speed. Here, we demonstrate an exchange-coupled asymmetric composite film structure of Ta/Pd/[Pd/Co]5/Cu(tCu)/[Co/Ni]5/Ta with adjustable strong perpendicular magnetic anisotropy and interlayer coupling strength, in which the dynamic magnetic properties are systematically studied by using time-resolved magneto-optical Kerr effect spectroscopy. It is demonstrated that the in-phase precession frequency is between those of the single hard magnetic [Pd/Co]5 and soft [Co/Ni]5 multilayers, which can be significantly enhanced for the strongly coupled case at tCu < 1 nm. Moreover, in the weakly coupled samples with tCu = 1.0-3.0 nm, besides the common in-phase acoustic mode, an out-of-phase optical mode occurs simultaneously with a frequency even higher than that of the hard magnetic [Pd/Co]5 layer. The optical mode precession frequency and amplitude show an unusual non-monotonic variation trend with the increase of tCu, which has been theoretically analyzed and attributed to the co-effect of decreased coupling strength and increased magnetic anisotropy field difference between the two multilayer stacks. Moreover, by adjusting tCu and the [Co/Ni] repetition number N, an optical mode of strong intensity can be actively achieved, even reaching 80% as compared to the acoustic mode. These results provide effective control and better understanding of magnetic dynamics in perpendicular composite films, which are of key importance for developing ultrafast spintronics-based devices.
AB - High frequency magnetic precessions with strong intensity are strongly desired in material systems for high performance magnetic memory or nano-oscillator applications with ultrafast manipulation speed. Here, we demonstrate an exchange-coupled asymmetric composite film structure of Ta/Pd/[Pd/Co]5/Cu(tCu)/[Co/Ni]5/Ta with adjustable strong perpendicular magnetic anisotropy and interlayer coupling strength, in which the dynamic magnetic properties are systematically studied by using time-resolved magneto-optical Kerr effect spectroscopy. It is demonstrated that the in-phase precession frequency is between those of the single hard magnetic [Pd/Co]5 and soft [Co/Ni]5 multilayers, which can be significantly enhanced for the strongly coupled case at tCu < 1 nm. Moreover, in the weakly coupled samples with tCu = 1.0-3.0 nm, besides the common in-phase acoustic mode, an out-of-phase optical mode occurs simultaneously with a frequency even higher than that of the hard magnetic [Pd/Co]5 layer. The optical mode precession frequency and amplitude show an unusual non-monotonic variation trend with the increase of tCu, which has been theoretically analyzed and attributed to the co-effect of decreased coupling strength and increased magnetic anisotropy field difference between the two multilayer stacks. Moreover, by adjusting tCu and the [Co/Ni] repetition number N, an optical mode of strong intensity can be actively achieved, even reaching 80% as compared to the acoustic mode. These results provide effective control and better understanding of magnetic dynamics in perpendicular composite films, which are of key importance for developing ultrafast spintronics-based devices.
UR - https://www.scopus.com/pages/publications/85070787243
U2 - 10.1039/c9cp02902h
DO - 10.1039/c9cp02902h
M3 - 文章
C2 - 31334707
AN - SCOPUS:85070787243
SN - 1463-9076
VL - 21
SP - 16830
EP - 16837
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 30
ER -