Topic
Monoclinic crystal system
About: Monoclinic crystal system is a research topic. Over the lifetime, 27019 publications have been published within this topic receiving 442766 citations. The topic is also known as: monoclinic.
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TL;DR: In this article, the structure of Li1−xNiO2 is studied as Li is electrochemically deintercalated from LiNiO 2 with in situ X-ray diffraction methods.
622 citations
TL;DR: In this paper, the crystal structure of β″, one of the strengthening phases in the commercially important Al-Mg-Si alloys, is determined by using of high resolution electron microscopy (HREM) and electron diffraction (ED).
604 citations
TL;DR: In this article, the origin of ultrahigh piezoelectricity in the relaxor ferroelectric PbZn(1/3)Nb(2/3)-PbTiO3 was studied with an electric field applied along the [001] direction.
Abstract: The origin of ultrahigh piezoelectricity in the relaxor ferroelectric PbZn(1/3)Nb(2/3)O3-PbTiO3 was studied with an electric field applied along the [001] direction. The zero-field rhombohedral R phase starts to follow the direct polarization path to tetragonal symmetry via an intermediate monoclinic M phase, but then jumps irreversibly to an alternate path involving a different type of monoclinic distortion. Details of the structure and domain configuration of this novel phase are described. This result suggests that there is a nearby R-M phase boundary as found in the Pb(Ti,Zr)O3 system.
585 citations
TL;DR: In this paper, it was shown that the 6th-order Devonshire theory cannot support a monoclinic phase, and an extension of the theory to higher orders was proposed.
Abstract: Devonshire theory provides a successful phenomenological description of many cubic perovskite ferroelectrics such as ${\mathrm{BaTiO}}_{3}$ via a sixth-order expansion of the free energy in the polar order parameter. However, the recent discovery of a novel monoclinic ferroelectric phase in the PZT system by Noheda et al. [Appl. Phys. Lett. 74, 2059 (1999)] poses a challenge to this theory. Here, we confirm that the sixth-order Devonshire theory cannot support a monoclinic phase, and consider extensions of the theory to higher orders. We show that an eighth-order theory allows for three kinds of equilibrium phases in which the polarization is confined not to a symmetry axis but to a symmetry plane. One of these phases provides a natural description of the newly observed monoclinic phase. Moreover, the theory makes testable predictions about the nature of the phase boundaries between monoclinic, tetragonal, and rhombohedral phases. A ferroelectric phase of the lowest (triclinic) symmetry type, in which the polarization is not constrained by symmetry, does not emerge until the Devonshire theory is carried to twelfth order. A topological analysis of the critical points of the free-energy surface facilitates the discussion of the phase transition sequences.
575 citations
TL;DR: UV-visible diffuse reflection spectra indicated that the BiVO(4) nanosheets had outstanding spectral selectivity and improved color properties compared with the corresponding bulk materials.
Abstract: Bismuth vanadate (BiVO(4)) nanosheets have been hydrothermally synthesized in the presence of sodium dodecyl benzene sulfonate (SDBS) as a morphology-directing template. The nanosheets were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) equipped with an X-ray energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), IR spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM (HR-TEM). The BiVO(4) nanosheets had a monoclinic structure, were ca. 10-40 nm thick, and showed a preferred (010) surface orientation. The formation mechanism and the effects of reaction temperature and time on the products were investigated. UV-visible diffuse reflection spectra indicated that the BiVO(4) nanosheets had outstanding spectral selectivity and improved color properties compared with the corresponding bulk materials. Furthermore, the nanosheets showed good visible photocatalytic activities as determined by degradation of N,N,N',N'-tetraethylated rhodamine (RB) under solar irradiation.
573 citations