TY - JOUR
T1 - Strain-induced modulation of perpendicular magnetic anisotropy in Ta/CoFeB/MgO structures investigated by ferromagnetic resonance
AU - Yu, Guoqiang
AU - Wang, Zhenxing
AU - Abolfath-Beygi, Maryam
AU - He, Congli
AU - Li, Xiang
AU - Wong, Kin L.
AU - Nordeen, Paul
AU - Wu, Hao
AU - Carman, Gregory P.
AU - Han, Xiufeng
AU - Alhomoudi, Ibrahim A.
AU - Amiri, Pedram Khalili
AU - Wang, Kang L.
N1 - Publisher Copyright:
© 2015 AIP Publishing LLC.
PY - 2015/2/16
Y1 - 2015/2/16
N2 - We demonstrate strain-induced modulation of perpendicular magnetic anisotropy (PMA) in (001)-oriented [Pb(Mg1/3Nb2/3)O3](1-x)-[PbTiO3]x (PMN-PT) substrate/Ta/CoFeB/MgO/Ta structures using ferromagnetic resonance (FMR). An in-plane biaxial strain is produced by applying voltage between the two surfaces of the PMN-PT substrate, and is transferred to the ferromagnetic CoFeB layer, which results in tuning of the PMA of the CoFeB layer. The strain-induced change in PMA is quantitatively extracted from the experimental FMR spectra. It is shown that both first and second-order anisotropy terms are affected by the electric field, and that they have opposite voltage dependencies. A very large value of the voltage-induced perpendicular magnetic anisotropy modulation of ∼7000 fJ/V·m is obtained through this strain-mediated coupling. Using this FMR technique, the magnetostriction coefficient λ is extracted for the ultrathin 1.1 nm Co20Fe60B20 layer, and is found to be 3.7 × 10-5, which is approximately 4 times larger than the previously reported values for CoFeB films thicker than 5 nm. In addition, the effect of strain on the effective damping constant (αeff) is also studied and no obvious modulation of the αeff is observed. The results are relevant to the development of CoFeB-MgO magnetic tunnel junctions for memory applications.
AB - We demonstrate strain-induced modulation of perpendicular magnetic anisotropy (PMA) in (001)-oriented [Pb(Mg1/3Nb2/3)O3](1-x)-[PbTiO3]x (PMN-PT) substrate/Ta/CoFeB/MgO/Ta structures using ferromagnetic resonance (FMR). An in-plane biaxial strain is produced by applying voltage between the two surfaces of the PMN-PT substrate, and is transferred to the ferromagnetic CoFeB layer, which results in tuning of the PMA of the CoFeB layer. The strain-induced change in PMA is quantitatively extracted from the experimental FMR spectra. It is shown that both first and second-order anisotropy terms are affected by the electric field, and that they have opposite voltage dependencies. A very large value of the voltage-induced perpendicular magnetic anisotropy modulation of ∼7000 fJ/V·m is obtained through this strain-mediated coupling. Using this FMR technique, the magnetostriction coefficient λ is extracted for the ultrathin 1.1 nm Co20Fe60B20 layer, and is found to be 3.7 × 10-5, which is approximately 4 times larger than the previously reported values for CoFeB films thicker than 5 nm. In addition, the effect of strain on the effective damping constant (αeff) is also studied and no obvious modulation of the αeff is observed. The results are relevant to the development of CoFeB-MgO magnetic tunnel junctions for memory applications.
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U2 - 10.1063/1.4907677
DO - 10.1063/1.4907677
M3 - Article
AN - SCOPUS:84923360956
SN - 0003-6951
VL - 106
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 7
M1 - 072402
ER -