Electric-field-driven magnetization reversal in square-shaped nanomagnet-based multiferroic heterostructure

Abstract

Articles you may be interested inSimultaneous imaging of the ferromagnetic and ferroelectric structure in multiferroic heterostructures APL Mat. 2, 076109 (2014); 10.1063/1.4890055Giant magneto-impedance effect in amorphous ferromagnetic wire with a weak helical anisotropy: Theory and experiment Based on phase field modeling and thermodynamic analysis, purely electric-field-driven magnetization reversal was shown to be possible in a multiferroic heterostructure of a square-shaped amorphous Co 40 Fe 40 B 20 nanomagnet on top of a ferroelectric layer through electrostrain. The reversal is made possible by engineering the mutual interactions among the built-in uniaxial magnetic anisotropy, the geometry-dependent magnetic configuration anisotropy, and the magnetoelastic anisotropy. Particularly, the incorporation of the built-in uniaxial anisotropy made it possible to reverse magnetization with one single unipolar electrostrain pulse, which is simpler than previous designs involving the use of bipolar electrostrains and may alleviate ferroelectric fatigue. Critical conditions for triggering the magnetization reversal are identified. V C 2015 AIP Publishing LLC.

Understanding and designing magnetoelectric heterostructures guided by computation: progresses, remaining questions, and perspectives

“…136,137 However, these proposals rely on the use of either a rotating piezostrain, 136 or a single-crystal magnet that shows two mutually perpendicular magnetic easy axes due to a four-fold magnetocrystalline anisotropy. 137 Recently, it has been shown that two pre-existing and mutually perpendicular magnetic easy axes can also appear in a flower-shaped magnetic nanodot with a fourfold shape anisotropy, 138 or in a square-shaped magnetic nanodot 139 with a four-fold magnetic configurational anisotropy 140 (see schematic in Fig. 7b).…”

“…7b). Using micromagnetic phasefield simulations, it was further shown that applying a bipolar 138 or unipolar 139 piezostrain pulse along the y-axis can switch the magnetization by 180°through two consecutive clockwise 90°m agnetization switching (see the arrows in Fig. 7b).…”

“…A familiar example is a magnetic domain-wall racetrack memory, 148 which is based on a current-induced fast magnetic domain-wall motion in a magnetic nanowire. However, it would be much more energy-efficient to drive 109 Strain-mediated electric-field-driven 180°magnetization switching in b a flower-shaped or a square-shaped nanomagnet fabricated on a piezoelectric bottom layer (substrate or film) via two consecutive 90°magnetization switching (see the arrows), adapted with permission, 138,139 and c an elliptic cylindrical nanomagnet on a piezoelectric film via precessional magnetization switching (see one possible spatial magnetization trajectory on the right), adapted with permission. 145 the motion of magnetic domain-walls with an electric field rather than a current.…”

Phase diagrams of magnetic state transformations in multiferroic composites controlled by size, shape and interfacial coupling strain

“…Strains/stresses couple to the magnetization via so-called magnetostrictive effect and modify the magnetic anisotropy. 7,8 As a consequence, strains/stresses have effects on the stability and transformation of polar and vortex states in submicron magnetic systems. Indeed, previous studies have shown that the direction of magnetization in the polar state can be reoriented by strain, which indicates the potential application in magnetic random access memory.…”

Research Update: Electrical manipulation of magnetism through strain-mediated magnetoelectric coupling in multiferroic heterostructures

“…Additionally, there have been several theoretical schemes to realize electric-field-tuned 180 • magnetization switching. 59,60 In the proposition, a flower-shaped 59 or square-shaped 60 nanomagnet with a fourfold symmetric shape anisotropy was deposited on FE materials. Significantly, there is a small angle mismatch between the anisotropic strain and the easy axis of the shape anisotropy resulting in a small energy barrier so that the magnetization can overcome this barrier with the assistance of an electric field.…”