DOMAIN STRUCTURE VARIATION WITH THICKNESS OF Nd2Fe14B SINGLE CRYSTAL

LiNbO3 (Mg:LN) crystal is an important electro-optical material and MgO-doped LiNbO3 was expected to improve its optical damage resistance. In the present work, we reported the Bridgman growth of MgO-doped LiNbO3 crystal. The growth parameters were discussed and the defects were investigated by the chemical etching method. The etch hillocks and etch pits were observed on the negative Z surface while only etch pits on the positive Z surface by the optical microscope and EPMA. The etching morphology was discussed considering the domain structure.

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Epitaxy of Nb3 Sn Films on Sapphire

MRS Proceedings ◽

10.1557/proc-37-517 ◽

1984 ◽

Vol 37 ◽

Cited By ~ 1

Author(s):

A. F. Marshall ◽

F. Hellman ◽

B. Oh

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Film Thickness ◽

Single Crystal ◽

Domain Structure ◽

High Temperatures ◽

Defect Structure ◽

Epitaxial Relationship ◽

Crystal Matrix ◽

Transmission Electron

AbstractFilms of Nb3Sn vapor deposited at low rates and high temperatures on (1102) sapphire form an epitaxial <100> single crystal matrix with a domain structure of misoriented regions bounded by low-angle dislocation boundaries. Nucleation of other orientations at the interface result in a highly oriented but polycrystalline film through approximately the first thousand Angstroms of film thickness. After this point random orientations become overgrown by epitaxial <100> regions. At slightly lower temperatures many small <100> grains with a second epitaxial relationship also nucleate at the interface. These rotated grains persist through greater thicknesses than random orientations. The misorientation defect structure of the single crystal matrix is analyzed by transmission electron microscopy.

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Phase Transformations in the Fe-Al System Studied by “In-Situ” Tem Heating

MRS Proceedings ◽

10.1557/proc-364-219 ◽

1994 ◽

Vol 364 ◽

Cited By ~ 2

Author(s):

A. Korner

Keyword(s):

Transition Temperature ◽

Single Crystal ◽

Domain Structure ◽

Type A ◽

Bimodal Distribution ◽

Dislocation Motion ◽

In Situ Tem ◽

Transmission Electron ◽

The Matrix

AbstractThe domain structure and the evolution of antiphase boundaries (APBs) have been investigated in Fe-Al by means of “in-situ” transmission electron microscopy (TEM) heating experiments. Single crystals with composition Fe22.1at%Al and Fe25.6at%Al have been used.The grown-in structure of the Fe22.1at%al single crystal is composed of DO3 ordered particles embedded in the disorderd ±-matrix. A bimodal distribution of the particles was found. Small ordered particles are in between the large precipitates which are surrounded by particle-free zones. Numerous of this large ordered precipitates contain APBs. Crossing the transition temperature to the disordered phase, the small particles dissolve into the ±-matrix and the large particles start to shrink by dissolving.The single crystal with composition Fe25.6at%Al was found to be completely DO3 ordered. The grown-in domains are separated by APBs of type a′0/2〈100〉. At temperatures far below the transition temperature to the B2 phase no significant change in the APB and domain structure has been detected. In contrast, a remarkable evolution in the APB structure has been observed approaching the transition temperature. Coarsening of the domains has been found. Furthermore, APBs of B2-type (a′0/4〈lll〉 shear) are dragged out by dislocation motion. B2- and DC3-type APBs react and junctions are formed. With increasing annealing time, the density of B2-type boundaries increases. The TEM image is dominated by B2-type boundaries linked by the D03-type boundaries. The DO3 superlattice spots are clearly excited approaching the transition temperature to B2. Above the transition temperature, the DO3 spots disappear completely and the diffraction pattern reveals B2 long range order.

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Electric field-induced crack growth and domain-structure evolution for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3) O3–28%PbTiO3 ferroelectric single crystals

Journal of Materials Research ◽

10.1557/jmr.2008.0415 ◽

2008 ◽

Vol 23 (12) ◽

pp. 3387-3395 ◽

Cited By ~ 13

Author(s):

F. Fang ◽

W. Yang ◽

F.C. Zhang ◽

H. Qing

Keyword(s):

Electric Field ◽

Crack Propagation ◽

Single Crystal ◽

Single Crystals ◽

Crack Growth ◽

Domain Structure ◽

Boundary Structure ◽

Structure Evolution ◽

In Situ Observation ◽

Oriented Single Crystal

In situ observation of the electrically induced crack growth and domain-structure evolution is carried out for [100]- and [101]-oriented 72%Pb(Mg1/3Nb2/3)O3–28% PbTiO3 (PMN–PT 72/28) ferroelectric single crystals under static (poling) and alternating electric fields. On the same poling electric field, domains are in the stable engineered domain state where four equivalent polarization variants coexist for [100]-oriented single crystal, while parallel lines representing the 71° domain boundaries appear for [101]-oriented one. Under the same cyclic electric field, the [100]-oriented single crystal shows much higher crack propagation resistance than that of a [101]-oriented crystal. Apart from the material aspects, such as crystallographic fracture anisotropy and non-180° domain boundary structure, crack boundary condition plays an important role in determining the crack propagation behavior.

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