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Title: Giant magnetoelectric coupling interaction in BaTiO{sub 3}/BiFeO{sub 3}/BaTiO{sub 3} trilayer multiferroic heterostructures

Abstract

Multiferroic trilayer thin films of BaTiO{sub 3}/BiFeO{sub 3}/BaTiO{sub 3} were prepared by RF-magnetron sputtering technique at different thicknesses of BiFeO{sub 3} layer. A pure phase polycrystalline growth of thin films was confirmed from X-ray diffraction results. The film showed maximum remnant electric polarization (2P{sub r}) of 13.5 μC/cm{sup 2} and saturation magnetization (M{sub s}) of 61 emu/cc at room temperature. Thermally activated charge transport dominated via oxygen vacancies as calculated by their activation energy, which was consistent with current–voltage characteristics. Magnetic field induced large change in resistance and capacitance of grain, and grain boundary was modeled by combined impedance and modulus spectroscopy in the presence of varied magnetic fields. Presence of large intrinsic magnetoelectric coupling was established by a maximum 20% increase in grain capacitance (C{sub g}) with applied magnetic field (2 kG) on trilayer having 20 nm BiFeO{sub 3} layer. Substantially higher magnetoelectric coupling in thinner films has been observed due to bonding between Fe and Ti atoms at interface via oxygen atoms. Room temperature magnetoelectric coupling was confirmed by dynamic magnetoelectric coupling, and maximum longitudinal magnetoelectric coupling of 515 mV/cm-Oe was observed at 20 nm thickness of BiFeO{sub 3}. The observed magnetoelectric properties are potentially useful for novel room temperature magnetoelectric and spintronic devicemore » applications for obtaining higher voltage at lower applied magnetic field.« less

Authors:
;  [1];  [2]
  1. CSIR-National Physical Laboratory, New Delhi 110012 (India)
  2. Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)
Publication Date:
OSTI Identifier:
22489170
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ATOMS; CAPACITANCE; CHARGE TRANSPORT; COUPLING; ELECTRIC POTENTIAL; GRAIN BOUNDARIES; MAGNETIC FIELDS; MAGNETIC PROPERTIES; MAGNETIZATION; MAGNETRONS; OXYGEN; POLARIZATION; POLYCRYSTALS; SPECTROSCOPY; SPUTTERING; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; TITANATES; X-RAY DIFFRACTION

Citation Formats

Kotnala, R. K., E-mail: rkkotnala@nplindia.org, E-mail: rkkotnala@gmail.com, Gupta, Rekha, and Chaudhary, Sujeet. Giant magnetoelectric coupling interaction in BaTiO{sub 3}/BiFeO{sub 3}/BaTiO{sub 3} trilayer multiferroic heterostructures. United States: N. p., 2015. Web. doi:10.1063/1.4929729.
Kotnala, R. K., E-mail: rkkotnala@nplindia.org, E-mail: rkkotnala@gmail.com, Gupta, Rekha, & Chaudhary, Sujeet. Giant magnetoelectric coupling interaction in BaTiO{sub 3}/BiFeO{sub 3}/BaTiO{sub 3} trilayer multiferroic heterostructures. United States. doi:10.1063/1.4929729.
Kotnala, R. K., E-mail: rkkotnala@nplindia.org, E-mail: rkkotnala@gmail.com, Gupta, Rekha, and Chaudhary, Sujeet. 2015. "Giant magnetoelectric coupling interaction in BaTiO{sub 3}/BiFeO{sub 3}/BaTiO{sub 3} trilayer multiferroic heterostructures". United States. doi:10.1063/1.4929729.
@article{osti_22489170,
title = {Giant magnetoelectric coupling interaction in BaTiO{sub 3}/BiFeO{sub 3}/BaTiO{sub 3} trilayer multiferroic heterostructures},
author = {Kotnala, R. K., E-mail: rkkotnala@nplindia.org, E-mail: rkkotnala@gmail.com and Gupta, Rekha and Chaudhary, Sujeet},
abstractNote = {Multiferroic trilayer thin films of BaTiO{sub 3}/BiFeO{sub 3}/BaTiO{sub 3} were prepared by RF-magnetron sputtering technique at different thicknesses of BiFeO{sub 3} layer. A pure phase polycrystalline growth of thin films was confirmed from X-ray diffraction results. The film showed maximum remnant electric polarization (2P{sub r}) of 13.5 μC/cm{sup 2} and saturation magnetization (M{sub s}) of 61 emu/cc at room temperature. Thermally activated charge transport dominated via oxygen vacancies as calculated by their activation energy, which was consistent with current–voltage characteristics. Magnetic field induced large change in resistance and capacitance of grain, and grain boundary was modeled by combined impedance and modulus spectroscopy in the presence of varied magnetic fields. Presence of large intrinsic magnetoelectric coupling was established by a maximum 20% increase in grain capacitance (C{sub g}) with applied magnetic field (2 kG) on trilayer having 20 nm BiFeO{sub 3} layer. Substantially higher magnetoelectric coupling in thinner films has been observed due to bonding between Fe and Ti atoms at interface via oxygen atoms. Room temperature magnetoelectric coupling was confirmed by dynamic magnetoelectric coupling, and maximum longitudinal magnetoelectric coupling of 515 mV/cm-Oe was observed at 20 nm thickness of BiFeO{sub 3}. The observed magnetoelectric properties are potentially useful for novel room temperature magnetoelectric and spintronic device applications for obtaining higher voltage at lower applied magnetic field.},
doi = {10.1063/1.4929729},
journal = {Applied Physics Letters},
number = 8,
volume = 107,
place = {United States},
year = 2015,
month = 8
}
  • Multiferroic (BaTiO{sub 3}-BiFeO{sub 3}) × 15 multilayer heterostructures show high magnetoelectric (ME) coefficients α{sub ME} up to 24 V/cm·Oe at 300 K. This value is much higher than that of a single-phase BiFeO{sub 3} reference film (α{sub ME} = 4.2 V/cm·Oe). We found clear correlation of ME coefficients with increasing oxygen partial pressure during growth. ME coupling is highest for lower density of oxygen vacancy-related defects. Detailed scanning transmission electron microscopy and selected area electron diffraction microstructural investigations at 300 K revealed antiphase rotations of the oxygen octahedra in the BaTiO{sub 3} single layers, which are an additional correlated defect structure of the multilayers.
  • In this paper, single-phase multiferroic ceramics of (1 - x) BaTiO{sub 3}-x BiFeO{sub 3} (BT - x BFO) were synthesized by solid-solution method in the wide range of material composition (x = 0.025 - 1.0). The changes in crystal structure were confirmed via X-ray diffractions (XRD) and atomic pair distribution functions (PDFs). The room-temperature ME coupling was found to exhibit significant magnitude in the narrow composition window (x = 0.71 - 0.8) where the average crystal structure was found to be rhombohedral. Especially, the BT - 0.725 BFO ceramics containing local monoclinic distortions within rhombohedral phase were found to exhibitmore » high room-temperature ME coefficient ({alpha}{sub ME}) of 0.87 mV/cm{center_dot}Oe with high piezoelectric properties (g{sub 33} = 18.5 Multiplication-Sign 10 mV m N{sup -1} and d{sub 33} = 124 pC N{sup -1}). We believe that the high room-temperature ME coupling in single-phase lead-free BT-BFO ceramics provides a possibility of developing electrically or magnetically tunable thin-film devices.« less
  • Magnetic spin structures in epitaxial BiFeO{sub 3} single layer and an epitaxial BaTiO{sub 3}/BiFeO{sub 3} multilayer thin film have been studied by means of nuclear resonant scattering of synchrotron radiation. We demonstrate a spin reorientation in the 15 × [BaTiO{sub 3}/BiFeO{sub 3}] multilayer compared to the single BiFeO{sub 3} thin film. Whereas in the BiFeO{sub 3} film, the net magnetic moment m{sup →} lies in the (1–10) plane, identical to the bulk, m{sup →} in the multilayer points to different polar and azimuthal directions. This spin reorientation indicates that strain and interfaces play a significant role in tuning the magnetic spin order.more » Furthermore, large difference in the magnetic field dependence of the magnetoelectric coefficient observed between the BiFeO{sub 3} single layer and multilayer can be associated with this magnetic spin reorientation.« less
  • Cited by 8
  • The electronic valence state of Mn in Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}/La{sub 0.8}Sr{sub 0.2}MnO{sub 3} multiferroic heterostructures is probed by near edge x-ray absorption spectroscopy as a function of the ferroelectric polarization. We observe a temperature independent shift in the absorption edge of Mn associated with a change in valency induced by charge carrier modulation in the La{sub 0.8}Sr{sub 0.2}MnO{sub 3}, demonstrating the electronic origin of the magnetoelectric effect. Spectroscopic, magnetic, and electric characterization shows that the large magnetoelectric response originates from a modified interfacial spin configuration, opening a new pathway to the electronic control of spin in complex oxide materials.