Enhanced exchange bias in fully epitaxial Fe ₃ O ₄ /tetragonal-like BiFeO ₃ magnetoelectric bilayers

Abstract

Fully epitaxial Fe3O4/BiFeO3 bilayers were deposited on (001) LaAlO3 and SrTiO3 by magnetron sputtering. BiFeO3 remained tetragonal on highly misfit-strain LaAlO3 substrates. Obvious exchange bias with a reciprocal relation to the thickness of ferromagnetic Fe3O4 was observed in the Fe3O4/tetragonal-like BiFeO3 (Fe3O4/T -BiFeO3) bilayers below ∼ 100 K which is similar to that of Fe3O4/rhombohedral-like BiFeO3 (Fe3O4/R-BiFeO3) bilayers. An unexpected enhancement of exchange bias from ∼ 160 Oe in Fe3O4/R-BiFeO3 to ∼ 320 Oe in the Fe3O4/T -BiFeO3 bilayer was observed at 3 K, which could be attributed to the enhanced Fe-O-Fe interfacial superexchange (SE) interaction induced by distorted T -BiFeO3.

Epitaxial growth of highly-crystalline spinel ferrite thin films on perovskite substrates for all-oxide devices

“…It is important to note that the magnetic moment of the film grown in the 3D-to-2D growth mode compares favorably with Fe 3 O 4 thin films from previous studies, with it exceeding the magnetic moment of previous Fe 3 O 4 films less than 100 nm thick grown on SrTiO 3 by any growth techniques3637424344. The other films in our study ( i .…”

“…For Fe 3 O 4 thin films (<100 nm), this results in films that have degraded physical properties ( e . g ., decreased magnetic moment) as compared to films grown on MgO, which due to a small lattice mismatch of ~0.3% with the spinel ferrites, allows for coherently strained growth of high-quality thin films202834353637.…”

Superior Properties of Energetically Stable La2/3Sr1/3MnO3/Tetragonal BiFeO3 Multiferroic Superlattices

“…The different phases of the BFO layer in the stack determine its ferroelectric polarization and subsequently the heterostructure properties. A high-quality tetragonal BFO film has been grown on LaAlO 3 substrate by pulsed laser deposition 25 or magnetron sputtering 26 , so one can deposit epitaxial LSMO layers on tetragonal BFO due to the good lattice match. Stronger magnetoelectric effect in the tetragonal BFO/LSMO heterostructures will stimulate further interest in developing the magnetoelectric controlled spintronic devices.…”

Mechanism of Fluorescence Enhancement of Biosynthesized XFe2O4–BiFeO3 (X = Cr, Mn, Co, or Ni) Membranes

“…2c. The clear diffraction peaks at 2θ angles (at approximately 22.5°, 31°, 46°, 28°, 31.5°, 36°, and 46.5°) and can be assigned to the (101), (012), and (202) characteristic reflections of BFO (JCPDS 20-0169) and the (220), (311), (222), and (440) characteristic reflections of the cubic structure of magnetite XFO (JCPDS 19-0629) [4, 8, 10]. The narrow and sharp peaks suggest that there is a highly crystalline nature (average crystalline sizes 4.5–5 nm) for the obtained XFO–BFO heterostructure.…”

“…To solve these problems, recent efforts have thus been focused on the complex structure of perovskite–spinel membrane [7]. This was realized previously by embedding small XFO seeds into a thin BFO layer [8], either by surface drilling or prepatterning [9], which guided the growth of the composite. In those previous articles [10], the p–n characterization of the templated nanocomposites was limited to macroscopical measurements at the remanence and interfacial coupling [11], ignoring the enhanced fluorescence at visible and near-infrared range that the few scattering centers can absorb most of the solar spectra.…”