“…It has been shown in the investigations of the domain structure of some boracites (Schmid, 1969; Schmid & Tippmann, 1978), that examination by means of PLM is the most direct method to reveal their static domain structure, as the polarization vector P s and optical indicatrix are differently orientated in every domain. Besides PLM, a number of different techniques are available for imaging domains in ferroelectric/ferroelastic crystals (for a review of these methods see Kahmann et al ., 1992; Lines & Glass, 1979), each of which has advantages and disadvantages depending on the ferroelectric material on hand. Thus, for example, SEM with its inherent higher resolution was for a long time not applicable to ferroelectric domain observations because of the charging of the specimen surface by the primary electron beam.…”
SummaryThe domain structures of Zn 3 B 7 O 13 Cl, Zn 3 B 7 O 13 Br and Zn 3 B 7 O 13 I boracite single crystals were studied by means of polarized light in conjunction with electron microscopy. Single crystals of the three compositions were grown by chemical transport reactions in closed quartz ampoules, at a temperature of 900 ° C and were examined by polarizing optical microscopy (PLM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For both PLM and SEM, the same as-grown samples were used without having to resort to metallization of the crystal faces. For TEM the single crystals were crushed and mounted on holey carbon films. Comparative electron microscope images were useful for revealing the domain structure of these ferroelectric/ferroelastic materials previously observed between the crossed polars of an optical microscope. X-ray diffraction analysis of the pulverized crystals was performed for this triad of halogen boracites containing zinc as a common metal.
“…It has been shown in the investigations of the domain structure of some boracites (Schmid, 1969; Schmid & Tippmann, 1978), that examination by means of PLM is the most direct method to reveal their static domain structure, as the polarization vector P s and optical indicatrix are differently orientated in every domain. Besides PLM, a number of different techniques are available for imaging domains in ferroelectric/ferroelastic crystals (for a review of these methods see Kahmann et al ., 1992; Lines & Glass, 1979), each of which has advantages and disadvantages depending on the ferroelectric material on hand. Thus, for example, SEM with its inherent higher resolution was for a long time not applicable to ferroelectric domain observations because of the charging of the specimen surface by the primary electron beam.…”
SummaryThe domain structures of Zn 3 B 7 O 13 Cl, Zn 3 B 7 O 13 Br and Zn 3 B 7 O 13 I boracite single crystals were studied by means of polarized light in conjunction with electron microscopy. Single crystals of the three compositions were grown by chemical transport reactions in closed quartz ampoules, at a temperature of 900 ° C and were examined by polarizing optical microscopy (PLM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For both PLM and SEM, the same as-grown samples were used without having to resort to metallization of the crystal faces. For TEM the single crystals were crushed and mounted on holey carbon films. Comparative electron microscope images were useful for revealing the domain structure of these ferroelectric/ferroelastic materials previously observed between the crossed polars of an optical microscope. X-ray diffraction analysis of the pulverized crystals was performed for this triad of halogen boracites containing zinc as a common metal.
“…In principle, this stochastic mechanism can be applied to all molecular crystals built from achiral dipolar compounds. , The first experimental proof to support this basic growth mechanism comes from scanning pyroelectric microscopy (SPEM) with which needle-shaped solution-grown crystals of size 1−3 mm in length and 0.2−0.5 mm in thickness have been investigated. , The SPEM technique also allows a tomographic view by layerwise thinning of crystals 7 and has currently achieved a lateral resolution of about 2.5 μm, averaging over a surface layer thickness of ∼10 μm . For an overview of conventional domain observation techniques for inorganic crystals, see ref . 1 (A) Schematic representation of the growth of PHTP host−guest (triangles−pills) crystals: interactions between acceptor (A) and donor (D) terminal groups [dark (A) and bright (D) cappings of the pills] control the alignment of guests during growth along channels.…”
Phase-sensitive second harmonic microscopy (PS-SHGM) opens up the possibility of imaging the bipolar state of Markov-type organic supramolecular crystals. During the cocrystallization of dipolar guest and nonpolar host compounds, channel-type inclusion compounds form crystals composed of adjacent macrodomains featuring opposite polarities. Through a comparison with crystals of known absolute polarity, the application of PS-SHGM allows a fast noncontact mapping of the domain structure and a determination of the absolute polarity of thin organic and other nonlinear opical crystals.
“…A certain number of techniques has been devised (for a review of known methods see, for example, Kahmann et al, 1992) for observing the domain structure of ferroelectric crystals, each of which offers advantages and disadvantages, depending on the ferroelectric material in hand. In the case of most boracites, for example, which undergo a phase transition from a high-temperature cubic phase (optically isotropic) to a low-temperature orthorhombic, tetragonal, monoclinic and/or trigonal (all optically anisotropic) phase, their domain structure has been traditionally studied by polarized-light microscopy (PLM) in both transmitted and reflected mode (Schmid, 1992).…”
SummaryCrystals of halogen manganese boracite, the mineral Mg 3 B 7 O 13 Cl, which is currently found in bedded sedimentary deposits of anhydrite, gypsum and halite, have been grown by chemical transport reactions and were examined by polarizing light microscopy and scanning electron microscopy. For both methods the same as-grown samples were used without having to metallize the crystal faces. Comparative electron microscope images were useful not only for observing the charging mechanism of an insulating sample bombarded by an electron beam but also for revealing the domain structure of these ferroelectric/ ferroelastic materials previously observed between the crossed polars of a light microscope. EDS qualitative analysis of the crystal faces was performed for the three compositions under study, i.e.
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