Spin waves in CoFeB on ferroelectric domains combining spin mechanics and magnonics

Abstract

Spin dynamics controlled by magnetoelastic coupling and applied electric fields might play a vital role in future developments of magnonics, i.e., the exploitation of spin waves for the transmission and processing of information.We have performed broadband spin-wave spectroscopy on a magnetostrictive CoFeB alloy grown on a ferrolectric BaTiO 3 substrate causing elastic strain with a quasi-periodic modulation. We find characteristic eigenfrequencies and spin-wave modes with large group velocities and small damping. These results suggest bright perspectives for electric-field control of reprogrammable magnonics.

Strain Mediated in‐Plane Uniaxial Magnetic Anisotropy in Amorphous CoFeB Films Based on Structural Phase Transitions of BaTiO3 Single‐Crystal Substrates

“…Unlike epitaxial systems, an amorphous FM film, such as one composed of CoFeB, involves isotropic magnetostriction as well as negligible magnetocrystalline anisotropy. Although magnonic devices containing CoFeB/BTO heterostructures have been demonstrated, the CoFeB/BTO heterostructures could help understand the strain induced magnetic anisotropy including dominant domain structure of BTO substrates. Therefore, the present study was intended to extend previous pioneering works to the case of heterostructures consisting of amorphous FM films in conjunction with ferroelectric substrates, such as CoFeB/BTO, and to understand the strain induced magnetic anisotropy quantitatively stemming from the BTO following the T → O structural phase transition as well as the related domain structure of the BTO.…”

Enhanced film thickness for Néel wall in soft magnetic film by introducing strong magnetocrystalline anisotropy

“…Considering that the domain wall exits in the film and the out-of-plane stray field cannot be detected through MFM, we can conclude that all of the magnetic moments lie in the film plane, and the domain wall is Néel wall. Note that, the Co 81 Ir 19 layer thickness is 50 nm which is higher than that of the reported Fe-and Co-based soft magnetic films 18 19 20 21 22 .…”

“…The domain wall assumes the form of Néel wall (the magnetic moments strictly lie in the film plane in the domain wall district) when the film is thin and it will become Bloch wall (an out-of-plane stray field exists in the domain wall district) when the film thickness exceeds a critical value. In conventional Fe- and Co-based soft magnetic films, this critical value is approximately 20–40 nm 18 19 20 21 22 . If the magnetocrystalline anisotropy energy is introduced to the soft magnetic film, the domain wall energy of Bloch wall expressed in eq.…”

Laser-Induced Magnetization Precession in Individual Magnetoelastic Domains of a Multiferroic Co40Fe40B20/BaTiO

“…In particular, full imprinting of ferroelastic domain patterns from FE substrates into FM overlayers with in-plane and perpendicular magnetizations and their subsequent manipulation by electric fields have been demonstrated experimentally [11][12][13][14][15][16][17]. FM-FE composites enable electric-field-induced magnetization switching, leading to changes in magnetoresistance [18][19][20][21][22], electrical tuning of ferromagnetic resonances and spin-wave spectra [23][24][25][26], active filtering and routing of propagating spin waves [27,28], and electrical switching between superconducting and normal states [29].…”