Influence of Annealing on Domain Structures of Bismuth-Titanate-Based Crystals

2006 ◽  
Vol 320 ◽  
pp. 27-30 ◽  
Author(s):  
Shinichi Katayama ◽  
Yuji Noguchi ◽  
Masaru Miyayama
Keyword(s):  
Rare Earth ◽  
Bismuth Titanate ◽  
Domain Walls ◽  
Antiphase Domain ◽  
Optical Microscope ◽  
Domain Structures ◽  
Domain Boundaries ◽  
Rare Earth La

Influence of annealing on the domain structures of bismuth titanate (BiT) and rare-earth (La and Nd)-substituted BiT crystals (BLT or BNT) were investigated by optical microscope and piezoresponse force microscope (PFM). Annealing of BiT at 950°C in air significantly decreased the number of striped 90° domain walls, while charged 180° domain walls were still present in the crystals after the annealing. The annealing for the crystals of BLT and BNT at the same condition did not change their 90° domain structures. PFM observations indicated that antiphase domain boundaries in BLT play an important role in the formation of 90° domain structures.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

Domain Dynamics of C-Axis Polarization in Bismuth Titanate Crystals

2007 ◽  
Vol 350 ◽  
pp. 69-72 ◽  
Author(s):  
Yuuki Kitanaka ◽  
Yuji Noguchi ◽  
Masaru Miyayama
Keyword(s):  
Electric Field ◽  
Remanent Polarization ◽  
Bismuth Titanate ◽  
Domain Walls ◽  
Polarization Switching ◽  
Optical Microscope ◽  
Saturated Polarization ◽  
Domain State ◽  
Initial Nucleus ◽  
Domain Dynamics

Polarization switching and domain dynamics in unpoled and poled crystals of bismuth titanate by applying electric field along the crystallographic c axis were investigated through polarization measurements and domain observations by optical microscope and piezoelectric force microscope. Poled crystals showed a well-saturated polarization hysteresis with a remanent polarization of 4.4 μC/cm2 and a coercive field of 4.7 kV/cm. Domain observations reveal that lenticular domain acts as an initial nucleus during polarization switching. The sidewise motion of the lenticular-domain walls and resultant single domain state were easily established for the poled crystals, while the lenticular domains observed in unpoled crystals were clamped even though a high electric field was applied to them.

Mapping of Magnetic Domains by MFM in Ni2MnGa

2008 ◽  
Vol 52 ◽  
pp. 115-119 ◽  
Author(s):  
Deepti Jain ◽  
Soma Banik ◽  
L.S. Sharath Chandra ◽  
S.R. Barman ◽  
R. Nath ◽  
...  
Keyword(s):  
Domain Walls ◽  
Alloy System ◽  
Optical Microscope ◽  
Magnetic Domains ◽  
Local Magnetization ◽  
Force Microscopy ◽  
Domain Structures ◽  
Two Samples ◽  
Ferromagnetic Shape Memory ◽  
Curie Temperature Tc

Influence of structural transition in the evolution of the magnetic domains in the ferromagnetic shape memory alloy system Ni2+xMn1-xGa is reported here using Magnetic Force Microscopy (MFM) studies. Studies reported are with two samples with their martensite transition temperature TM less than and greater than the Curie temperature Tc. Present results show an evolution of MFM across the Tc with a clear twin domains and sub domain structures inside the twins. The higher spatial resolution of MFM (~50nm) as compared to optical microscope (400nm) is useful in probing the domain walls. Force derivative of the MFM signal that may be used as an order parameter seems to scale the onset of magnetic order in the system. One can clearly see the vanishing of the MFM patterns for T>Tc. Results are discussed in the light of models available for tip-sample interactions that track the local magnetization.

Domain pattern formation in ferroelastic Pb3(PO4)2 by computer simulation

1997 ◽  
Vol 12 (9) ◽  
pp. 2366-2373 ◽  
Author(s):  
K. Parlinski ◽  
Y. Kawazoe
Keyword(s):  
Monoclinic Phase ◽  
Domain Walls ◽  
Symmetry Axis ◽  
Antiphase Domain ◽  
Annealing Process ◽  
Domain Pattern ◽  
Lead Phosphate ◽  
Calculated Density ◽  
Domain Structures ◽  
Form Domain

A model of lead phosphate, which describes the rhombohedral-monoclinic phase transition, is used to form domain patterns in the annealing process. The obtained domain structures show W and W′ types of domain walls in agreement with the stress-free laws proposed in Sapriel's theory. The observed W domain walls are parallel to the ternary symmetry axis, while the W′ ones are tilted with respect to the same axis. The antiphase domain walls take no preferential orientations, and remain parallel to the ternary axis. The calculated density of the potential energy of the domain wall of type W is estimated to be Edw = 49 K/Å2 at T = 300 K.

DO3-domain Structures in Fe3Al-X Alloys

1984 ◽  
Vol 39 ◽  
Author(s):  
Madan G. Mendiratta ◽  
Harry A. Lipsitt
Keyword(s):  
Transformation Temperature ◽  
Antiphase Domain ◽  
Atomic Percent ◽  
Ti Alloy ◽  
Domain Structures ◽  
Domain Boundaries ◽  
Ternary Additions

ABSTRACTThe influence of a number ternary additions in Fe3Al upon the DO3 domain structures and DO3 → B2 transformation temperature, Tc, has been investigated. It was found that additions in (atomic percent) of 5 Ti, 5 Cr, 6 Mn, 12 Mn, 10 Ni, 3 Mo, 6 Mo, 3 Si, and 5 Si raise Tc. In the Fe-20 Al-5 Ti alloy not only is Tc raised significantly (≧ 750°C), but the DO3 antiphase domain boundaries with fault vector become highly crystallographic and are parallel to {100} planes.

On the Formation of High Damping State in Fe-Al and Fe-Cr Alloys

2008 ◽  
Vol 137 ◽  
pp. 109-118 ◽  
Author(s):  
I.B. Chudakov ◽  
Nataly A. Polyakova ◽  
S.Yu. Mackushev ◽  
V.A. Udovenko
Keyword(s):  
Domain Structure ◽  
Domain Walls ◽  
Volume Fraction ◽  
Magnetic Domain ◽  
Al Alloys ◽  
The State ◽  
Magnetic Domain Structure ◽  
Damping Capacity ◽  
Domain Structures ◽  
Domain Boundaries

High damping Fe - Cr and Fe - Al alloys have been studied in two different states: in the high damping state and in the suppressed damping capacity state. It has been shown that magnetic domain structures of Fe - Cr and Fe - Al alloys are fundamentally different in the high damping state and in the state with the suppressed damping. Magnetic domain structure corresponding to the high damping state can be characterized by an enhanced volume fraction of the easy movable 90o-domain walls, but the state with the suppressed damping capacity can be characterized by the enhanced volume fraction of the 180o-domain boundaries.

Effect of Rare Earth La Modification on Microstructure and Properties of ZL101 Alloy

2011 ◽  
Vol 675-677 ◽  
pp. 651-654 ◽  
Author(s):  
Xiu Mei Zhang ◽  
Zhi Ming Shi ◽  
Rui Ying Zhang
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Brinell Hardness ◽  
Optical Microscope ◽  
Microstructure And Properties ◽  
Microstructure And Mechanical Properties ◽  
Small Load ◽  
La Modification ◽  
Rare Earth La ◽  
Scanning Electron

In this paper, rare earth La modifying ZL101 alloy was studied by using of optical microscope, scanning electron microscopy, universal materials tester and small-load Brinell hardness. The influence of T6 heat treatment of the alloy’s microstructure and properties was also studied. The results show that microstructure and mechanical properties of the alloy have much obvious modification effect at modification temperature (690°C). The microstructure and mechanical properties are improved remarkably when La content is up to 0.15wt%.

Antiphase Boundaries in Ordered Ni3FE Crystals

1969 ◽  
Vol 27 ◽  
pp. 62-63
Author(s):  
Y. H. Liu
Keyword(s):  
Domain Size ◽  
Antiphase Domain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardening Mechanism ◽  
Superlattice Structure ◽  
Disordered Phase ◽  
Domain Boundaries ◽  
Atomic Scattering ◽  
The Difference

Ordered Ni3Fe crystals possess a LI2 type superlattice similar to the Cu3Au structure. The difference in slip behavior of the superlattice as compared with that of a disordered phase has been well established. Cottrell first postulated that the increase in resistance for slip in the superlattice structure is attributed to the presence of antiphase domain boundaries. Following Cottrell's domain hardening mechanism, numerous workers have proposed other refined models also involving the presence of domain boundaries. Using the anomalous X-ray diffraction technique, Davies and Stoloff have shown that the hardness of the Ni3Fe superlattice varies with the domain size. So far, no direct observation of antiphase domain boundaries in Ni3Fe has been reported. Because the atomic scattering factors of the elements in NijFe are so close, the superlattice reflections are not easily detected. Furthermore, the domain configurations in NioFe are thought to be independent of the crystallographic orientations.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

The observation of solutions in Ni3Nb

1988 ◽  
Vol 46 ◽  
pp. 540-541
Author(s):  
Z.M. Wang ◽  
J.P. Zhang
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Phase Modulation ◽  
High Resolution Electron Microscopy ◽  
Antiphase Domain ◽  
Boundary Area ◽  
Matrix Type ◽  
Resolution Electron ◽  
Domain Boundaries ◽  
Kontorova Model

High resolution electron microscopy reveals that antiphase domain boundaries in β-Ni3Nb have a hexagonal unit cell with lattice parameters ah=aβ and ch=bβ, where aβ and bβ are of the orthogonal β matrix. (See Figure 1.) Some of these boundaries can creep “upstairs” leaving an incoherent area, as shown in region P. When the stepped boundaries meet each other, they do not lose their own character. Our consideration in this work is to estimate the influnce of the natural misfit δ{(ab-aβ)/aβ≠0}. Defining the displacement field at the boundary as a phase modulation Φ(x), following the Frenkel-Kontorova model [2], we consider the boundary area to be made up of a two unit chain, the upper portion of which can move and the lower portion of the β matrix type, assumed to be fixed. (See the schematic pattern in Figure 2(a)).

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