Strain-mediated converse magnetoelectric coupling strength manipulation by a thin titanium layer

Abstract

The manipulation of the strain-mediated magnetoelectric (ME) coupling strength is investigated by inserting a thin Ti layer (0–10 nm) between a 50 nm Co50Fe50 layer and a (011) oriented lead magnesium niobate-lead titanate (PMN-PT) substrate. A record high remanence ratio (Mr/Ms) tunability of 100% has been demonstrated in the 50 nm CoFe/8 nm Ti/PMN-PT heterostructure, when a total in-plane piezoelectric strain of −1821 ppm was applied at an electric field (E-field) of 16 kV/cm. The ME coupling strength is gradually optimized as the Ti layer thickness increases. Magnetic energy calculation showed that with increasing Ti layer thickness the uniaxial magnetic anisotropy energy (Euni) was reduced from 43 ± 1 kJ/m3 to 29.8 ± 1 kJ/m3. The reduction of Euni makes the strain effect dominant in the total magnetic energy, thus gives an obvious enhanced ME coupling strength.

Strain-induced structural, magnetic and ferroelectric properties of heterostructure BST–NZFO nanocomposite thin film at room temperature

“…Generally the magnetic properties in NZFO-BST-Si and BST-NZFO-Si composite films emerge due to connection of ferroelectric grain with neighbouring ferrite grain. The observation of large magnetization in BST-NZFO-Si composite thin film is an extraordinary finding and is mainly attributed to the presence of smaller particles, large strain and formation of defect states at the interface of composite phase [10][11][12][13][14][15][16]. As the particles size in ferrite phase of BST-NZFO-Si is smaller, the surface effect becomes dominant, i.e., as the volume to surface ratio of particles decreases, the uncompensated surface magnetic spin induced by the confinement of small nanoparticles significantly contributes to improved magnetic properties [17][18][19][20].…”

“…The lattice strain at the interface of composite-layered thin films plays a crucial role in the enhancement of magnetoelectric coupling between the composites phases. Recently, strain-induced magnetoelectric properties were discovered in many materials, which allow electric field control of magnetic properties [11][12][13]. In pursuit of achieving the highest magnetoelectric coupling in composite multiferroic thin films, different composites nanostructures such as 0-3 particulate composite (bulk), 2-2 laminates composite and 1-3 fibrerod composite films have been investigated to a large extent [5][6][7][8].…”

Artificial multiferroic structures using soft magnetostrictive bilayers on Pb(Mg1/3Nb2/3)–PbTiO3

“…Although an increase in the NiFe thickness did not decrease the anisotropy and coercive fields further. [12]. Insets for both graphs is the positive and negative electric field dependence for the 10nm and 25nm NiFe/50nm FeCo structure.…”

“…The bottom Au electrode was left on the substrate, while the top electrode was polished off to leave a smooth PMN-PT surface for the magnetic films to be grown on. A thin 10nm Ti layer was evaporated onto the PMN-PT substrate, as this had been shown from previous work to give a random texture orientation within the FeCo film, which increases the magnetostriction constant [12]. Before growth the silicon substrates were cleaned using acetone followed by isopropanol alcohol (IPA).…”

Influence of Ar Pressure on the Magnetic Properties of Amorphous FeGaSiB Thin Films

“…These applications include low field sensors and artificial multiferroic heterostructures, which use electric fields to control the magnetisation via the strain induced by the piezoelectric substrate [5,6].…”