Strain Modulation of Perpendicular Magnetic Anisotropy in Wrinkle-Patterned (Co/Pt)₅/BaTiO₃ Magnetoelectric Heterostructures

Abstract

The rapid development of spintronics requires the devices to be flexible, to be used in wearable electronics, and controllable, to be used with magnetoelectric (ME) structures. However, the clamping effect inevitably leads to a decreased ME effect on the rigid substrate, and it remains challenging to directly prepare high-quality ferroelectric (FE) membranes on the widely used flexible substrate such as MICA or polyimide (PI). Here, periodic wrinkle-patterned flexible (Co/Pt)5/BaTiO3 (BTO) perpendicular magnetic anisotropy (PMA) heterostructures were prepared using the water-soluble method. The high-quality single-crystal BTO membrane ensures that intricate wrinkles do not fracture and a high ME coefficient is achievable. The transferred sample that is released from the clamping effect shows an enhanced ME effect in both in-plane and out-of-plane directions, with the ME coefficient reaching up to 68 Oe °C–1. The ferromagnetic resonance (FMR) field of the flexible sample can be tuned by tensile strain up to 272 Oe. The finely controlled wrinkle shows periodic strain variations at peak and valley regions that switch the PMA magnetic domain motion as an effective control method. The proposed ultraflexible wrinkle sample shows great potential for combining multiple magnetization tuning approaches, allowing it to potentially serve as a tunable high-density 3D storage prototype.

Enhanced Stress Stability in Flexible Co/Pt Multilayers with Strong Perpendicular Magnetic Anisotropy

“…These results not only explain our experimental results very well but also provide a feasible solution to designing flexible magnetic materials and devices with enhanced stress stability. As magnetic thin films with PMA are advantageous in constructing magnetic memory and logic devices with high density and good thermal stability, − our results suggest that flexible magnetic materials with strong PMA could be promising for constructing high-performance magnetoelectronic devices with enhanced stress stability.…”

Directed Self-Assembly of Oxide Nanocomposites by Ion-Beam Lithography

“…BiFeO 3 –CoFe 2 O 4 (BFO–CFO) is the best-studied VAN, in which strain transfer between the ferroelectric perovskite BFO and ferrimagnetic spinel CFO leads to enhanced magnetoelectric coupling at room temperature . VANs can also consist of metals or alloys, e.g., Au, Ag, Fe, Ni, Co, and Pt, codeposited with functional oxides such as SrTiO 3 or BaTiO 3 , − broadening the compositions and the scope of applications of VANs.…”

Freestanding Perovskite Oxide Membranes: A New Playground for Novel Ferroic Properties and Applications

“…Reproduced with permission. [ 73 ] Copyright 2022, American Chemical Society. c) Piezoelectric force microscopy image of the freestanding BTO‐CFO nanostructure.…”