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The article presents a study focusing on strain-induced modulation of perpendicular magnetic anisotropy (PMA) in tantalum(Ta)/cobalt iron boron (CoFeB)/magnesium oxide (MgO) structures investigated by ferromagnetic resonance. The findings include strain-induced change in PMA extracted from the experimental ferromagnetic resonance (FMR) spectra, modulation of the PMA of an ultrathin CoFeB layer by voltage-induced strain and dependence of the effective damping constant as a function of strain.

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 x 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 (aeff) is also studied and no obvious modulation of the aeff is observed. The results are relevant to the development of CoFeB-MgO magnetic tunnel junctions for memory applications. [ABSTRACT FROM AUTHOR]