Gate-controlled magnon-assisted switching of magnetization in ferroelectric/ferromagnetic junctions

Abstract

Interfacing a ferromagnet with a polarized ferroelectric gate generates a non-uniform, interfacial spin density coupled to the ferroelectric polarization. This coupling allows for an electric field control of the effective field acting on the magnetization. To unravel the usefulness of this interfacial magneto-electric coupling we investigate the magnetization dynamics of a ferroelectric/ferromagnetic multilayer structure using the Landau-Lifshitz-Baryakhtar equation. The results demonstrate that the interfacial magnetoelectric coupling is utilizable as a highly localized and efficient tool for manipulating magnetism by electrical means. Ways of enhancing the strength of the interfacial coupling and/or its effects are discussed.

Magnon-tuning non-volatile magnetic dynamics in a CoZr/PMN-PT structure

“…The interfacial spin density can be viewed as a magnonic accumulation stabilized by the P of the FE layer at the coupled FE/FM interface, which modifies of the magnitude of the interfacial local magnetic moments. Here we are interested in the interfacial spin density s || , whose direction adiabatically follows the intrinsic magnetization M at an instant of time, and which is given as: s || = ησ FE e -z/λ / λ 16 – 18 , 20 , where η is the spin polarization of the electron density in the CoZr layer in the Stoner mean-field theory, σ FE is the surface charge density, and λ is the effective spin diffusion length in the CoZr layer. Therefore, a major effect on the CoZr layer induced by this magnon-driven ME coupling is the change of the intrinsic magnetization, given as ΔM || = ησ FE µ B / d , with d being the thickness of the CoZr layer.…”

“…Moreover, the range of spiral spin density can reach the order of nanometers, which has a clear advantage in allowing non-volatile device for information storage. This can be viewed as magnonic accumulation that is stabilized by the charge rearrangement between the coupled FE (with an FE polarization P) and FM (with an FM magnetization M) [14][15][16][17][18][19][20] . Thus, it is predicted that the magnon-driven interfacial ME coupling-induced changes in the magnetic anisotropy will lead to elastic magnetic dynamics in the FM layer.…”

Global weak solution of the Landau-Lifshitz-Baryakhtar equation

“…This equation Date: February 10, 2023. has also been implemented on several commonly used micromagnetic simulation software, such as MuMax [2,23] and Fidimag [28,29]. Moreover, various micromagnetic simulations provide evidence that the LLBar equation agrees with some of the observed experimental findings in micromagnetics, especially those related to ultrafast magnetisation at an elevated temperature; see [2,12,25,28,29,30] and the references therein.…”

Dynamical anisotropic magnetoelectric effects at ferroelectric/ferromagnetic insulator interfaces*

“…[13] On the other hand, a comprehensive understanding of coupling between spin and charge degrees of freedoms in the insulating interface state of composite multiferroics is still missing. In artificial FE/FM multiferroics, the studies on the interfacial ME effect have thus far remained interesting such as the electrostatic screening effect, [5,[14][15][16][17] ionic liquid gating, [18][19][20] orbital reconstruction, [20][21][22][23][24] etc. However, this electric field effect can be ruled out in case of the FM insulator (FMI) interfaces due to the absence of mobile charge carriers.…”