Microstructural analysis of interfaces in a ferromagnetic-multiferroic epitaxial heterostructure

Abstract

We report a study on multiferroic bismuth ferrite ͑BiFeO 3 , BFO͒-ferromagnetic lanthanum strontium manganese oxide ͑La 0.7 Sr 0.3 MnO 3 , LSMO͒ epitaxial interfaces by scanning transmission electron microscopy-energy dispersive spectroscopy ͑STEM-EDS͒ and energy-filtered transmission electron microscopy ͑EFTEM͒. Epitaxial ͑001͒ oriented LSMO/BFO heterostructures were fabricated on a ͑001͒ strontium titanate ͑SrTiO 3 , STO͒ substrate using pulsed laser deposition ͑PLD͒. Different cooling conditions to room temperature ͑rapid or slow͒ were used to investigate the effect of fabrication conditions on the structural quality of the interfaces. The combined analysis of bright field transmission electron microscopy imaging, STEM-EDS and EFTEM data reveals that the LSMO-BFO heterostructure interface is free from any defects but the phases are chemically interdiffused over a length scale of ϳ4 nm.

Exploring the Magnetoelectric Coupling at the Composite Interfaces of FE/FM/FE Heterostructures

“…The multiple interfaces that exist in the heterostructures can lead to carrier confinement effects, magnetic interactions, and lattice strain effects at the interface that play an important role in determining the physical and functional properties of the material 36–39 . Therefore, detailed studies of the interface structure are essential to understand many novel physical phenomena observed in heterostructures.…”

Analysis of Ferromagnetic-Multiferroic Interfaces in Epitaxial Multilayers of LSMO and BFO

“…Further research into and development of these novel heterostructures could demonstrate unusual uses only appropriate for these materials. 1,2 It is believed that the end result of this research…”

“…Introduction -Traditionally, ferroelectric and ferromagnetic materials have been used for actuators, optoelectronic devices, capacitors, information storage devices, and sensors. 1 However, recently, multiferroic materials, materials which demonstrate both magnetic and ferroelectric properties, have piqued great interest. This unique combination of ferromagnetic and ferroelectric ordering means these materials have a wide range of potential uses for which standard ferromagnetic and ferroelectric materials are not ideally suited.…”

“…2 In multiferroic materials, electric polarization can be used to influence ferromagnetic polarization, thereby manipulating magnetization and ferromagnetic ordering. 1 Multilayer heterostructures of these materials are of particular interest, because they allow for control of electron spin polarization which has a number of applications in the area of magnetic sensors and devices. Further research into and development of these novel heterostructures could demonstrate unusual uses only appropriate for these materials.…”

Chemistry of the Fe2O3/BiFeO3 Interface in BiFeO3 Thin Film Heterostructures

“…Moreover BFO has a very narrow thin film deposition window to obtain phase pure BFO thin films, which necessitates a rigid control in terms of the precursor chemistry, temperature and oxygen pressure, to synthesize the films. For example, incorrect Bi concentration in the targets can create secondary phases, such as Fe 2 O 3 [6,7], while improper oxygen environments during laser ablation can lead to pockets of Bi 2 O 3 [6]; on the other hand, high growth temperatures can also lead to cation diffusion across the thin film interfaces [8]. Additionally, it has been found that oxygen vacancies could induce significant leakage current [9,10].…”