Papers by Keyword: Domain Structure

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Authors: J.L. Muñoz, G.V. Kurlyandskaya, José M. Barandiarán, A.P. Potapov, Manuel Vázquez
Authors: M.B. Sagdatkireeva, V.V. Rumyantseva, N.A. Khasanov
Abstract: The characteristics of the periodic fine structure in domain walls in oblique-evaporated films of quantum-well (QW) thickness with an easy-magnetization axis inclined with respect to the normal to the film plane has been studied. It is pointed out that the self-organization of domain structures is related to the quantum character of the cooperative phenomenon of ferromagnetism [. The spectrum of magnetoelastic waves has been calculated for films of iron type.
Authors: Vitaly Yu. Topolov, A.V. Turik
Authors: Masazumi Arao, Yasuhide Inoue, Ryoutarou Ando, Yasumasa Koyama
Abstract: To understand dielectric properties around the ferroelectric tetragonal (FT)/rhombohedral (FR) phase boundary in Pb1-xLax(Zr1-yTiy)O3, the crystallographic features of ferroelectric states around the boundary have been investigated by transmission electron microscopy. It was found that, when the Ti content approached to the phase boundary in the FT-phase area, a dielectric property became the relaxor behavior. The corresponding change in the crystallographic features is that the usual FT state is converted into the nanometer-sized coexisting state of the ferroelectric monoclinic (FM) and FR phases. Because the crystal structure of FR-phase regions in the coexisting state involves the R25-type rotational displacement of oxygen octahedra, the FR phase can be identified as the low-temperature ferroelectric rhombohedral phase that is present in Pb(Zr1-yTiy)O3. It is thus understood that the relaxor behavior found in Pb1-xLax(Zr1-yTiy)O3 should be associated with the presence of the nanometer-sized coexisting state that consists of two ferroelectric phases.
Authors: Hirofumi Tsukasaki, Yasuhide Inoue, Yasumasa Koyama
Abstract: The relaxor state has been found in the mixed ferroelectric system Ba (Ti1-xZrx)O3 around x = 0.35. To understand the nature of the relaxor state, the crystallographic features of the paraelectric (PC), ferroelectric, and relaxor states for 0.15 ≤ x ≤ 0.40 have been investigated mainly by transmission electron microscopy. It was found that a microstructure of the ferroelectric state for 0.15 ≤ x ≤ 0.28 consisted of banded structures with boundaries parallel to the {110}PC and {100}PC planes. Based on the Sapriel theory concerning ferroelastic transitions, it was understood that the banded structures were consistent with domain structures in the ferroelectric rhombohedral (FR) state having a polarization vector parallel to one of the <111>PC directions. With the help of the failure of Friedel’s law in diffraction, furthermore, polar regions having <001>PC and <110>PC components of a <111>PC polarization vector were also found to be separately observed in the PC and relaxor states as well as the FR state. Then, in-situ observation for 0.29 ≤ x ≤ 0.40 made in this study indicated that the PC and relaxor states consisted of polar nanometer-sized regions having these two components. Based on this, the relaxor state in BTZ can be identified as an assembly of polar nanometer-sized regions, which were produced by the suppression of the (PC→FR) ferroelectric transition on cooling.
Authors: Shotaro Ishikawa, Yuuki Kitanaka, Yuji Noguchi, Masaru Miyayama, Chikako Moriyoshi, Yoshihiro Kuroiwa
Abstract: Domain structures and dynamics of BaTiO3 single crystals under in-situ electric fields along <110>c were investigated by using synchrotron radiation single-crystal X-ray diffractions. Diffraction patterns clearly show the presence of a 90 ° domain structure in the crystals poled along <110>c. The diffraction analysis provides direct evidence of a reversible change in the volume fractions of two kinds of the 90 o domains under unipolar in-situ electric fields. This reversible change in the domain structures under unipolar fields is suggested to originate from the interaction between spontaneous polarization and defect dipoles composed of acceptor and oxygen vacancy.
Authors: M. Tuominen, Rositza Yakimova, A. Kakanakova-Georgieva, Mike F. MacMillan, Mikael Syväjärvi, Erik Janzén
Authors: Yu.N. Dragoshanskii, V.V. Shulika, A.P. Potapov, V.F. Tiunov
Abstract: The paper deals with the domain structure and electromagnetic characteristics of soft magnetic iron-based alloys, which are formed by the impact of thermomagnetic treatment (TMT) - cooling of the material in the presence of a magnetic field. The effect of reducing the specific magnetic loss in materials, using a constant or alternating (different frequency) magnetic field is determined. It is shown that the minimum magnetic losses in the materials are obtained after TMT in an alternating magnetic field at high (~ 80 kHz) frequencies. This shows up the perspectives of TMT of soft magnets.
Authors: V.E. Zubov, A.D. Kudakov, N.L. Levsнin, M.Yu. Gusev, N.S. Neustroev
Abstract: Due to water molecules adsorption the reversible change of domains width and domain structure reconstruction in bismuth-doped ferrite-garnet thin films with perpendicular magnetic anisotropy was observed. The change of domains width was 15% in saturated water vapor at room temperature. The decrease of domains width is explained by the reduction of effective perpendicular magnetic anisotropy constant due to water molecules adsorption.
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