Multiferroic heterostructures for spintronics

Abstract

For next-generation technology, magnetic systems are of interest due to the natural ability to store information and, through spin transport, propagate this information for logic functions. Controlling the magnetization state through currents has proven energy inefficient. Multiferroic thin-film heterostructures, combining ferroelectric and ferromagnetic orders, hold promise for energy efficient electronics. The electric field control of magnetic order is expected to reduce energy dissipation by 2–3 orders of magnitude relative to the current state-of-the-art. The coupling between electrical and magnetic orders in multiferroic and magnetoelectric thin-film heterostructures relies on interfacial coupling though magnetic exchange or mechanical strain and the correlation between domains in adjacent functional ferroic layers. We review the recent developments in electrical control of magnetism through artificial magnetoelectric heterostructures, domain imprint, emergent physics and device paradigms for magnetoelectric logic, neuromorphic devices, and hybrid magnetoelectric/spin-current-based applications. Finally, we conclude with a discussion of experiments that probe the crucial dynamics of the magnetoelectric switching and optical tuning of ferroelectric states towards all-optical control of magnetoelectric switching events.

Roadmap on Magnetoelectric Materials and Devices

“…2(b)). Such utilization of the ME effect was enabled by the attainment of ME heterostructures with strong ME coupling [13][14][15][16][17][18][19][20][21][22][23][24][25], which results in large ME coefficients. Given the two kinds of ME coupling-direct and converse ME effects-two coefficients have been defined to quantify the coupling strength:…”

Charged Domain Wall and Polar Vortex Topologies in a Room Temperature Magnetoelectric Multiferroic Thin Film

“…Room temperature multiferroic materials, possessing coupled ferroelectric and ferromagnetic states, have exciting potential for use in future low-energy data-storage devices such as magnetoelectric-spin orbit logics for recurring neural networks. [1][2][3] Layered oxide thin films such as the Bi2O2(Am−1B mO3m+1) Aurivillius phase offer a flexible template for designing new multiferroic materials, where m is the number of perovskite units interleaved between the (Bi2O2) 2+ fluorite-type layers. [4][5] Aurivillius phases are established ferroelectric materials with strong in-plane polarisations, 6 high Curie temperatures (>600°C) and fatigue-free energy storage performance.…”

“…[7][8][9] The rare possibility of room temperature ferromagnetism within a ferroelectric framework is achieved in Aurivillius phases with the introduction of magnetic ions within the scaffold. 10-14 15 Bi6TixFeyMnzO18 ( x = 2.80 to 3.04; Y = 1.32 to 1.52; Z = 0.54 to 0.64) 16 where m = 5, is an example of such an ion-substituted multiferroic Aurivillius phase, displaying saturation magnetization (MS) values of 215 emu/cm 3 , with in-plane saturation polarization (Ps) values of >26 µC/cm 2 and with experimentally proven magnetoelectric switching. Bi6TixFeyMnzO18 (B6TFMO) can be thought of as a 2D nanostructured framework, with 5 perovskite cells sandwiched between dielectric (Bi2O2) 2+ layers.…”

Charged Domain Wall and Polar Vortex Topologiesin a Room Temperature Magnetoelectric Multiferroic Thin Film

“…Room temperature multiferroic materials, possessing coupled ferroelectric and ferromagnetic states, have exciting potential for use in future low-energy data-storage devices such as magnetoelectric-spin orbit logics for recurring neural networks. [1][2][3] Layered oxide thin films such as the Bi2O2(Am−1B mO3m+1) Aurivillius phase offer a flexible template for designing new multiferroic materials, where m is the number of perovskite units interleaved between the (Bi2O2) 2+ fluorite-type layers. [4][5] Aurivillius phases are established ferroelectric materials with strong in-plane polarisations, 6 high Curie temperatures (600°C) and fatigue-free energy storage performance.…”

“…[7][8][9] The rare possibility of room temperature ferromagnetism within a ferroelectric framework is achieved in Aurivillius phases with the introduction of magnetic ions within the scaffold. 10-14 15 Bi6TixFeyMnzO18 ( x = 2.80 to 3.04; Y = 1.32 to 1.52; Z = 0.54 to 0.64) 16 where m = 5, is an example of such an ionsubstituted multiferroic Aurivillius phase, displaying saturation magnetization (MS) values of 215 emu/cm 3 , with in-plane saturation polarization (Ps) values of 26 C/cm 2 and with experimentally proven magnetoelectric switching. Bi6TixFeyMnzO18 (B6TFMO) can be thought of as a 2D nanostructured framework, with 5 perovskite cells sandwiched between dielectric (Bi2O2) 2+ layers.…”