Control of the nanostructure in percolative multiferroic composites on the dielectric loss and magnetism threshold

Abstract

Revealing clearly the control of microstructure on dielectric and magnetic properties of multiferroic composite is of great importance in designing the composite with high performance. In this paper, the BTO/NZFO composite thin films with solid solution constituent phases around 20 nm were prepared by RF magnetron sputtering. The lattice constant, grain size, intrinsic and extrinsic oxygen vacancies and non-stoichiometric defect in the nanocomposite thin film are measured by XRD, TEM and XPS. The conductivity, dielectric properties and magnetic performances of the nanocomposite are measured by impedance analyzer and MPMS respectively.In this multisusceptible nanocomposite thin film, the permittivity is compatible with Kirkpatrick model, and the dielectric loss is controlled importantly by the high fraction of grain boundary which restrains the charge migration and makes thus the loss low significantly. The saturation magnetization of the nanocomposite thin film is influenced mainly by the lattice deformation of nanosized constituent phases. The magnetic threshold of the nanocomposite shifts low from the real topological one, which is profitable for the composite to contribute simultaneously the low dielectric loss and high permeability. The coercivity, which is controlled by the grain size of NZFO and magnetic communication among NZFO nanoparticles, displays a novel percolation behavior.increasing ferrite content when x < 0.6 and keeps stable when x > 0.6; and the lattice constant of the NZFO phase decreases slowly with increasing ferrite when x < 0.4 and speedily when x > 0.4 in the (1−x)BTO/xNZFO composite. Fig. 3(c) exhibits the grain sizes of the BTO and NZFO phases in the composite thin film which are calculated from the X-ray diffraction peak by Scherer's equation.The grain size of the NZFO phase increases linearly from 14.3 nm to 20.0 nm while that of the BTO

Control of Oxygen Vacancies in TiO6 Octahedra of Amorphous BaTiO3 Thin Films with Tunable Built‐In Electric Field in a‐BaTiO3/p‐Si Heterojunction for Metal–Oxide–Semiconductor Applications

“…The binding energy of about 531 eV is typical for absorbed hydroxyl groups, whereas the binding energy of about 529 eV is similar to that reported in crystalline perovskite BTO . In the crystalline phase, the absorption O is related to O vacancy in the TiO 6 octahedron . However, for the thin film, if the phase structure does not form well, such as in the amorphous status with significant defects and dangling bonds, the defects, as well as the O vacancies, will form simultaneously .…”

“…In general, the O vacancies in the crystalline phase are always detected by the XPS spectra of O 1s . As shown in Figure c, two XPS peaks of O 1s can be observed.…”

“…In the crystalline phase, the absorption O is related to O vacancy in the TiO 6 octahedron . However, for the thin film, if the phase structure does not form well, such as in the amorphous status with significant defects and dangling bonds, the defects, as well as the O vacancies, will form simultaneously . The hydroxyl groups from the atmosphere will be absorbed by two kinds of absorption centers in this case, and will be detected at about 531 eV in O 1s XPS spectra.…”

Anisotropy of Percolation Threshold of BaTiO3-Ni0.5Zn0.5Fe2O4 Composite Films

“…However, for the composite films with the ferrite fraction lying between 0.2 and 0.8, the permittivity under an out-of-plane electric field is slightly higher than that under an in-plane field. It is known that the permittivity of the BTO-NZFO composite films conforms with the Kirkpatrick model 23 . In Fig.…”

A tri-phase percolative ceramic composite with high initial permeability and composition-independent giant permittivity

“…Many efforts have been devoted to the investigation of multiferroic materials both experimentally and theoretically due to their capability to satisfy the fast growing demands in advanced electronic devices, such as memory devices with multi-state data storage, solid-state transformers and high sensitivity magnetic eld sensors. [1][2][3][4][5][6] Ferroelectric/ferromagnetic composite materials are potential candidates to meet the requirements of miniaturization and multi-functionality in next-generation electronic devices. For example, integrated capacitance-inductance elements and anti-electro-magnetic interference (anti-EMI) lters usually require more space saving in circuit boards or replacement of passive lters constructed from separate capacitance and inductance elements in order to realize the purpose of miniaturization and multi-functionality simultaneously.…”