Low-Voltage Control of (Co/Pt)_x Perpendicular Magnetic Anisotropy Heterostructure for Flexible Spintronics

Abstract

The trend of mobile Internet requires portable and wearable devices as bio-device interfaces. Electric field control of magnetism is a promising approach to achieve compact, light-weight, and energy-efficient wearable devices. Within a flexible sandwich heterostructure, perpendicular magnetic anisotropy switching was achieved via low-voltage gating control of an ionic gel in mica/Ta/(Pt/Co) /Pt/ionic gel/Pt, where (Pt/Co) acted as a functional layer. By conducting in situ VSM, EPR, and MOKE measurements, a 1098 Oe magnetic anisotropy field change was determined at the bending state with tensile strain, corresponding to a magnetic anisotropy energy change of 3.16 × 10 J/m and a giant voltage tunability coefficient of 0.79 × 10 J/m·V. The low voltage and strain dual control of magnetism on mica substrates enables tunable flexible spintronic devices with an increased degree of manipulation.

Voltage Control of Perpendicular Exchange Bias in Multiferroic Heterostructures

“…At the IL/film interface, there are opposite charge accumulations forming an electric double layer (EDL) with a thickness ≈3 nm . As demonstrated by our previous work, the ultrahigh surface charge density (up to 10 15 per cm 2 ) in EDL could lead to fascinating interfacial ME phenomena . During our gating experiments (including some results not shown here), we find that these is no obvious loop shift until gating voltage ( V g ) reaches 2 V; when V g keeps increasing to 3 V and eventually 4 V, the loop offset becomes stronger and stronger, as shown in Figure e.…”

Sunlight Control of Interfacial Magnetism for Solar Driven Spintronic Applications

“…Enlightened by the recent progress of organic semiconductor solar cells (OSSCs) and ionic liquid (IL) charge doping modulation of interfacial ferromagnetism, we have designed a photovoltaic spintronics demo with optical-magnetic-electro (OME) tricoupled OSSC/magnetic heterojunction to overcome the current challenges of optical control of magnetism. [11,[24][25][26][27][28][29][30][31][32][33] Here, the OSSC films under visible light can provide a large number of photo-induced electron accumulation in the cobalt ferromagnetic layer, which may influence the Fermi level of FM thin films and then change the magnetic properties. [11,[24][25][26][34][35][36][37] Compared with IL gating method, the optical gating process is a pure physical routine without any possible chemical change and erosive problem.…”

“…[11,[24][25][26][27][28][29][30][31][32][33] Here, the OSSC films under visible light can provide a large number of photo-induced electron accumulation in the cobalt ferromagnetic layer, which may influence the Fermi level of FM thin films and then change the magnetic properties. [11,[24][25][26][34][35][36][37] Compared with IL gating method, the optical gating process is a pure physical routine without any possible chemical change and erosive problem. [11] In addition, this process also applies to flexible electronics/spintronics/photonics for its compatibility with flexible substrates.…”

Strain-Enhanced Charge-to-Spin Conversion in Ta/Fe/Pt Multilayers Grown on Flexible Mica Substrate

“…The integration of an electronic system with a flexible substrate has received considerable attention due to the appealing applications in alternative devices such as flexible display, electronic skin, and wearable devices [1][2][3][4][5]. The fantastic property of such flexible electronics also triggers numerous research efforts in the spintronics field on the flexible strain effects of spin-dependent phenomena such as exchange bias [6,7], interlayer coupling [8], and perpendicular magnetic anisotropy (PMA) [9]. In recent years, the focus of modern spintronics has been shifted to the generation and manipulation of pure spin currents through spin-orbit coupling (SOC) in nonmagnetic systems [10][11][12], the studies of which even give birth to an emerging field, that is, spin orbitronics [13].…”