Visible Light Effects on Photostrictive/Magnetostrictive PMN‐PT/Ni Heterostructure

Abstract

The possibility of modifying the ferromagnetic response of a multiferroic heterostructure via fully optical means exploiting the photovoltaic/photostrictive properties of the ferroelectric component is an effective method for tuning the interfacial properties. In this study, the effects of 405 nm visible‐light illumination on the ferroelectric and ferromagnetic responses of (001) Pb(Mg1/3Nb2/3)O3‐0.4PbTiO3 (PMN‐PT)/Ni heterostructures are presented. By combining electrical, structural, magnetic, and spectroscopic measurements, how light illumination above the ferroelectric bandgap energy induces a photovoltaic current and the photostrictive effect reduces the coercive field of the interfacial magnetostrictive Ni layer are shown. Firstly, a light‐induced variation in the Ni orbital moment as a result of sum‐rule analysis of x‐ray magnetic circular dichroic measurements is reported. The reduction of orbital moment reveals a photogenerated strain field. The observed effect is strongly reduced when polarizing out‐of‐plane the PMN‐PT substrate, showing a highly anisotropic photostrictive contribution from the in‐plane ferroelectric domains. These results shed light on the delicate energy balance that leads to sizeable light‐induced effects in multiferroic heterostructures, while confirming the need of spectroscopy for identifying the physical origin of interface behavior.

Reversible optical control of magnetism in engineered artificial multiferroics

“…It is well-known that PMN-PT exhibits photostriction when it is illuminated with UV light as a result of a converse piezoresponse induced by the photovoltage engendered by the bulk photovoltaic effect. 3,4 Two crucial facts should be taken into account: (i) although piezoelectric materials have large mechanical response to electric fields, the visible-light-driven deformation will not be activated if they do not have an appropriate domain structure containing charged domain walls; (ii) even in ferroelectrics with charged domain walls, large light-driven anisotropic deformation is obtained only when an adequate domain configuration is designed. As hypothesis, other ferroelectric materials exhibiting stripe-shaped charged domain walls may manifest visible-light-induced strain.…”

“…Light-induced control of magnetism is a promising technology for the implementation of novel magnetoelectronic devices because it is a non-contact actuation method that entails ultralow power dissipation. [1][2][3][4][5][6][7] Unfortunately, deterministic and reversible control of magnetic properties using light has proven to be challenging and, so far, restricted to a few specific materials with still limited commercial viability. 8 For this reason, the scientific community has turned its attention to multiferroic materials which are highly appealing owing to their magnetoelastic and magnetoelectric properties.…”

Graphene Magnetoresistance Control by Photoferroelectric Substrate

“…The Pb­[(Mg 1/3 Nb 2/3 ) 0.70 ­Ti 0.30 ]­O 3 (PMN-PT30%) crystal with dimensions of 1.49 × 0.78 × 0.3 mm 3 was cut from plates of (001) orientation supplied by Crystal-GmbH (Germany). This ferroelectric compound belongs to the PMN-PT family of low-electric-field switchable crystals reported to manifest a large scale of interesting properties ranging from electro-optic − and piezoelectric − to photovoltaic ,,, and photostrictive. , …”

Single Wavelength Operating Neuromorphic Device Based on a Graphene–Ferroelectric Transistor

“…The single crystals of Pb­[(Mg 1/3 Nb 2/3 ) 0.70 Ti 0.30 ]­O 3 were ordered from Crystal GmbH (Germany). These compounds are low-electric field switchable FE crystals of so-called PMN-PT family reported to manifest large scale of interesting properties ranging from piezoelectric , and electro-optic , to PV , and photostrictive. , After CVD graphene deposition, the sample was annealed and a piece of 1.87 mm by 0.82 mm was cut from the 10 mm 2 wafer of 0.3 mm thickness. The lateral drain and source electrodes deposition of Ti­(5 nm)/Au­(30 nm) layers was done by E-beam evaporation via a shadow mask and wired using the silver conductive paste.…”