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Ferrite Film (ferrite + film)

Distribution by Scientific Domains
Polymers and Materials Science50%
Physics and Astronomy50%

Selected Abstracts

Unraveling Deterministic Mesoscopic Polarization Switching Mechanisms: Spatially Resolved Studies of a Tilt Grain Boundary in Bismuth Ferrite

ADVANCED FUNCTIONAL MATERIALS, Issue 13 2009
Brian J. Rodriguez
Abstract The deterministic mesoscopic mechanism of ferroelectric domain nucleation is probed at a single atomically-defined model defect: an artificially fabricated bicrystal grain boundary (GB) in an epitaxial bismuth ferrite film. Switching spectroscopy piezoresponse force microscopy (SS-PFM) is used to map the variation of local hysteresis loops at the GB and in its immediate vicinity. It is found that the the influence of the GB on nucleation results in a slight shift of the negative nucleation bias to larger voltages. The mesoscopic mechanisms of domain nucleation in the bulk and at the GB are studied in detail using phase-field modeling, elucidating the complex mechanisms governed by the interplay between ferroelectric and ferroelastic wall energies, depolarization fields, and interface charge. The combination of phase-field modeling and SS-PFM allows quantitative analysis of the mesoscopic mechanisms for polarization switching, and hence suggests a route for unraveling the mechanisms of polarization switching at a single defect level and ultimately optimizing materials properties through microstructure engineering. [source]

Giant Electric Field Tuning of Magnetic Properties in Multiferroic Ferrite/Ferroelectric Heterostructures

ADVANCED FUNCTIONAL MATERIALS, Issue 11 2009
Ming Liu
Abstract Multiferroic heterostructures of Fe3O4/PZT (lead zirconium titanate), Fe3O4/PMN-PT (lead magnesium niobate-lead titanate) and Fe3O4/PZN-PT (lead zinc niobate-lead titanate) are prepared by spin-spray depositing Fe3O4 ferrite film on ferroelectric PZT, PMN-PT and PZN-PT substrates at a low temperature of 90,°C. Strong magnetoelectric coupling (ME) and giant microwave tunability are demonstrated by a electrostatic field induced magnetic anisotropic field change in these heterostructures. A high electrostatically tunable ferromagnetic resonance (FMR) field shift up to 600,Oe, corresponding to a large microwave ME coefficient of 67,Oe cm kV,1, is observed in Fe3O4/PMN-PT heterostructures. A record-high electrostatically tunable FMR field range of 860 Oe with a linewidth of 330,380,Oe is demonstrated in Fe3O4/PZN-PT heterostructure, corresponding to a ME coefficient of 108,Oe cm kV,1. Static ME interaction is also investigated and a maximum electric field induced squareness ratio change of 40% is observed in Fe3O4/PZN-PT. In addition, a new concept that the external magnetic orientation and the electric field cooperate to determine microwave magnetic tunability is brought forth to significantly enhance the microwave tunable range up to 1000,Oe. These low temperature synthesized multiferroic heterostructures exhibiting giant electrostatically induced tunable magnetic resonance field at microwave frequencies provide great opportunities for electrostatically tunable microwave multiferroic devices. [source]

NiZnCu Ferrite Thick Film with Nano Scale Crystallites Formed by the Aerosol Deposition Method

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2004
Maxim Lebedev
This paper describes the magnetic properties of NiZnCu ferrite film deposited at room temperature by an aerosol deposition method (ADM). The thickness of the film was 6 ,m and the deposition rate was estimated as 2 ,m/min. The microstructure of as-deposited at room temperature films consists of randomly oriented nanocrystallites with a size of 20 nm. As-deposited and annealed films exhibited the following magnetic properties: intensity of magnetization Ms= 0.147 T (117 emu/cm3), coercivity Hc= 40.58 kA/m (510 Oe); and Ms= 0.3 T (250 emu/cm3), Hc= 14.95 kA/m (188 Oe), respectively. [source]

The influence of substrate on the magnetic properties of MnZn ferrite thin film fabricated by alternate sputtering

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2008
Lanxi Wang
Abstract Mn0.5Zn0.5Fe2O4 film which has the highest saturation magnetization among Mn1,xZnx Fe2O4 thin films was prepared by the alternate rf sputtering method from two targets with compositions of MnFe2O4 and ZnFe2O4, respectively. The films were deposited on single-crystal Si(100), MgO(100) and SiO2/Si(100) substrates. The as-deposited films were amorphous, and after annealing in a vacuum furnace at 550 °C, polycrystalline MnZn ferrite films with residual amorphous matrix were obtained. The coercivity of all films is low, and the film on the MgO(100) substrate shows a coercivity as low as 27 Oe. The grain size of all films is about 20 nm and is less than the ferromagnetic exchange length (160 nm), so magnetic anisotropies are averaged to lower effective values. Furthermore, the negative magnetostriction constant of crystalline MnZn ferrite and the positive magnetostriction constant of amorphous Fe-based matrix will cancel out and may lead to a low or vanishing saturation magnetostriction constant. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Pinning energy of domain walls in MnZn ferrite films

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2007
V. H. Calle
Abstract Mn Zn ferrite films deposited on (100) MgO substrates by rf sputtering technique with different thicknesses , in the range of 30-450 nm were studied. AFM images show grain size increase as film thickness increases. Grains with diameters between L , 70 and 700 nm were observed. The mono and multidomain regime in MnZn ferrite films and their effect on the pinning energy of domain walls are observed via Magneto-optical Kerr Effect, MOKE. At , , 300 nm, the coercive field, Hc, reaches a maximum value of 80 Oe. This result indicates the existence of a multidomain regime associated to a critical grain size, Lc. We used the Jiles-Atherton model (JAM) to discuss the experimental hysteresis loops. The k pinning parameter obtained from JAM shows a maximum value of k /,o = 67 Am2 for grains with Lc , 529 nm. The total energy per unit area E was correlated with k and D. We found a simple phenomenological relationship given by E , kD; where D is the magnetic domain width. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]