scholarly journals Synthesis, Structure and Magnetic Properties of NiFe3O5

2022 ◽  
Author(s):  
Ka Hong ◽  
Elena Solana ◽  
Mauro Coduri ◽  
Clemens Ritter ◽  
Paul Attfield
Keyword(s):  
Exchange Interactions ◽  
Neutron Diffraction Data ◽  
Cation Site ◽  
Cell Parameters ◽  
Site Distribution ◽  
Rich Variety ◽  
Ordered Phases ◽  
The Rich ◽  
Cation Size ◽  
Cation Sites

Abstract A new CaFe3O5-type phase NiFe3O5 (orthorhombic Cmcm symmetry, cell parameters a = 2.89126(7), b = 9.71988(21) and c = 12.52694(27) Å) has been synthesised under pressures of 12-13 GPa at 1200 °C. NiFe3O5 has an inverse cation site distribution and reveals an interesting evolution from M2+(Fe3+ )2Fe2+O5 to Fe2+(M2+ 0.5Fe3+ 0.5)2Fe3+O5 distributions over three distinct cation sites as M2+ cation size decreases from Ca to Ni. Magnetic susceptibility measurements show successive transitions at 275, ~150, and ~20 K and neutron diffraction data reveal a series of at least three spin-ordered phases with evolving propagation vectors k = [0 0 0] [0 ky 0]  [½ ½ 0] on cooling. The rich variety of magnetically ordered phases in NiFe3O5 likely results from frustration of Goodenough-Kanamori exchange interactions between the three spin sublattices, and further interesting magnetic materials are expected to be accessible within the CaFe3O5-type family.

Site occupancy in gamma alumina

1996 ◽  
Vol 54 ◽  
pp. 654-655
Author(s):  
C. A. Bateman ◽  
A.Z. Ringwelski ◽  
R.W. Broach
Keyword(s):  
Spinel Structure ◽  
Site Occupancy ◽  
Unit Cell ◽  
Neutron Diffraction Data ◽  
Gamma Alumina ◽  
Tetrahedral Sites ◽  
Powder Neutron Diffraction ◽  
Cation Sites ◽  
Powder Neutron Diffraction Data ◽  
Insufficient Number

Gamma (γ) alumina is referred to as a defect spinel because it has a tetragonally distorted spinel structure (AB2O4) and an insufficient number of cations to fill all cation sites. In the spinel structure, the oxygen lattice is cubic close packed with A- and B-site cations in tetrahedral and octahedral coordination, respectively. The 2l⅓ Al atoms per unit cell of γ alumina can distribute themselves across 16 octahedral and 8 tetrahedral sites.The literature differs on where the 2⅔ cation vacancies per unit cell are located. Wilson and McConnell proposed that the vacancies in γ alumina, as first formed by calcining boehmite, are predominantly on the tetrahedral lattice but, with further heat treatment, move to occupy random positions on both octahedral and tetrahedral lattices. One study using NMR showed that the vacancies lay exclusively on the tetrahedral lattice, independent of the calcination temperature. A more-recent study using Rietveld refinement of powder neutron diffraction data suggested that both octahedral and tetrahedral lattices were partially occupied.

Introduction

2017 ◽  
Author(s):  
Travis D. Stimeling
Keyword(s):  
United States ◽  
The United States ◽  
Country Music ◽  
Future Research ◽  
Music Culture ◽  
Rich Variety ◽  
Ethnographic Studies ◽  
Folklore Studies ◽  
History Of ◽  
The Rich

This chapter offers a historiographic survey of country music scholarship from the publication of Bill C. Malone’s “A History of Commercial Country Music in the United States, 1920–1964” (1965) to the leading publications of the today. Very little of substance has been written on country music recorded since the 1970s, especially when compared to the wealth of available literature on early country recording artists. Ethnographic studies of country music and country music culture are rare, and including ethnographic methods in country music studies offers new insights into the rich variety of ways in which people make, consume, and engage with country music as a genre. The chapter traces the influence of folklore studies, sociology, cultural studies, and musicology on the development of country music studies and proposes some directions for future research in the field.

scholarly journals Quasi-1D XY antiferromagnet Sr2Ni(SeO3)2Cl2 at Sakai-Takahashi phase diagram

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. S. Kozlyakova ◽  
A. V. Moskin ◽  
P. S. Berdonosov ◽  
V. V. Gapontsev ◽  
S. V. Streltsov ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Long Range ◽  
Density Functional ◽  
Uniaxial Anisotropy ◽  
Exchange Interactions ◽  
Spin Liquid ◽  
Functional Theory ◽  
One Dimensional ◽  
Ordered Phases ◽  
Experimental Findings

AbstractUniform quasi-one-dimensional integer spin compounds are of interest as a potential realization of the Haldane conjecture of a gapped spin liquid. This phase, however, has to compete with magnetic anisotropy and long-range ordered phases, the implementation of which depends on the ratio of interchain J′ and intrachain J exchange interactions and both uniaxial D and rhombic E single-ion anisotropies. Strontium nickel selenite chloride, Sr2Ni(SeO3)2Cl2, is a spin-1 chain system which passes through a correlations regime at Tmax ~ 12 K to long-range order at TN = 6 K. Under external magnetic field it experiences the sequence of spin-flop at Bc1 = 9.0 T and spin-flip transitions Bc2 = 23.7 T prior to full saturation at Bsat = 31.0 T. Density functional theory provides values of the main exchange interactions and uniaxial anisotropy which corroborate the experimental findings. The values of J′/J = 0.083 and D/J = 0.357 place this compound into a hitherto unoccupied sector of the Sakai-Takahashi phase diagram.

Rethinking emotion in discursive psychology: A systemic functional perspective

2019 ◽  
Vol 26 (2) ◽  
pp. 211-233
Author(s):  
Jiaxing Jiang ◽  
Jingyuan Zhang
Keyword(s):  
Conceptual Analysis ◽  
Significant Part ◽  
Discursive Psychology ◽  
Emotion Words ◽  
Rich Variety ◽  
Functional Perspective ◽  
The Rich ◽  
Psychological Studies

Emotion, as a classic topic in psychological studies, has been intensively investigated by scholars across disciplines. In discursive psychology, emotion discourse refers to the rich variety and situated uses of emotion words and metaphors. Many studies of emotion in discursive psychology focus on the rhetorical contrasts of emotion. Conceptual analysis is another significant part of emotion discourse, and one that requires further investigation. To reveal how people describe and evoke emotions in discourse, this article starts with a reinterpretation of emotion in discursive psychology, followed by setting up an emotion system from a systemic functional perspective to illustrate how conceptual analysis may be conducted and rhetorical contrasts explored. During the process of establishing the emotion system, the paper elaborates upon the emotion concept and rhetorical contrasts on the basis of four illustrative examples taken from authentic extracts (including news and testimonies). The paper discusses the purpose behind the construction of the emotion system in terms of (1) the constituents in conceptual analysis and rhetorical contrasts of discursive psychology from a functional perspective, (2) the collaboration between conceptual analysis and rhetorical contrasts, (3) the traits of the emotion system as a method of discursive psychology analysis.

Regional Identities and Cultures of Medieval Jews

2018 ◽  
Keyword(s):  
Middle Ages ◽  
North Africa ◽  
Western Europe ◽  
Regional Identity ◽  
Asia Minor ◽  
The Balkans ◽  
Rich Variety ◽  
Regional Cultures ◽  
The Rich ◽  
The Middle Ages

Though the existence of Jewish regional cultures is widely known, the origins of the most prominent groups, Ashkenaz and Sepharad, are poorly understood, and the rich variety of other regional Jewish identities is often overlooked. Yet all these subcultures emerged in the Middle Ages. Scholars contributing to the present study were invited to consider how such regional identities were fashioned, propagated, reinforced, contested, and reshaped — and to reflect on the developments, events, or encounters that made these identities manifest. They were asked to identify how subcultural identities proved to be useful, and the circumstances in which they were deployed. The resulting volume spans the ninth to sixteenth centuries, and explores Jewish cultural developments in western Europe, the Balkans, North Africa, and Asia Minor. In its own way, each chapter considers factors — demographic, geographical, historical, economic, political, institutional, legal, intellectual, theological, cultural, and even biological — that led medieval Jews to conceive of themselves, or to be perceived by others, as bearers of a discrete Jewish regional identity. Notwithstanding the singularity of each chapter, they collectively attest to the inherent dynamism of Jewish regional identities.

Leucite-pollucite structure-type variability and the structure of a synthetic end-member calcium wairakite (CaAl2Si4O12·2H2O)

1998 ◽  
Vol 62 (2) ◽  
pp. 165-178 ◽  
Author(s):  
C. M. B. Henderson ◽  
A. M. T. Bell ◽  
S. C. Kohn ◽  
C. S. Page
Keyword(s):  
Rietveld Analysis ◽  
Structure Type ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Synthetic Sample ◽  
Cation Site ◽  
Wide Range ◽  
Angle Spinning ◽  
Cation Sites

AbstractThe structure of a synthetic end-member wairakite (CaAl2Si4O12·2H2O) has been determined using Rietveld analysis of high-resolution, synchrotron X-ray powder diffraction data, and 29Si and 27Al magic angle spinning nuclear magnetic resonance spectroscopy. The framework in the synthetic sample is more disordered than that in natural wairakite. Ca is distributed over the cavity cation sites M2, M12A, M12B in the approximate proportions 0.8:0.1:0.1, respectively, with M11 being vacant. 29Si MAS NMR data are consistent with about 80% of the Si occupying tetrahedral T11 and T12 sites linked to two Al atoms [Q4(2Al) silicons]. Tetrahedral and cavity cation site disorder are coupled so that Al mainly occupies T2 sites, with Ca in M12A and M12B being balanced by Al in T12A and T12B; T11A and T11B sites appear to only contain Si, in agreement with the M11 site being vacant. The crystal chemistries of the wide range of stoichiometries which crystallize with the leucite/pollucite structure-type are also reviewed, with particular attention being paid to the tetrahedral ordering configurations present in these phases, and the implications to crystallographic phase transitions.

Cultural Heritage Programs in the Higher Education Institutions: The Bulgarian Experience

2021 ◽  
Vol 29 (2) ◽  
pp. 143-153
Author(s):  
Vera Boneva
Keyword(s):  
Higher Education ◽  
Cultural Heritage ◽  
Education System ◽  
Doctoral Programs ◽  
Higher Education Institutions ◽  
Complex Structure ◽  
Scientific Field ◽  
Higher Education System ◽  
Rich Variety ◽  
The Rich

The article systematizes information about the current cultural heritage programs in the Bulgarian higher education area. The data shows that in eleven Bulgarian universities a diploma of cultural heritage can be obtained. 17 master's and 3 bachelor's programs prepare over 500 students a year. Two doctoral programs are also accredited. The rich variety of curricula is an objective result of the complex structure of cultural heritage in itself. However, it is also an indicator for the fragmentation of the higher education system in Bulgaria. The conclusion proposes approaches to overcoming the mentioned fragmentation, as the interdisciplinarity of the scientific field requires pooling of competencies and efforts for better results.

“Heart of Darkness” on The Bulgarian Stage – Creative Perspectives and Techniques

Proglas ◽  
2019 ◽  
Vol 28 (1) ◽  
Author(s):  
Petya Tsoneva ◽  
◽  
Margreta Grigorova ◽  
◽  
◽  
...  
Keyword(s):  
Edgar Allan Poe ◽  
Fantastic Literature ◽  
Stage Design ◽  
Work Related ◽  
Rich Variety ◽  
Successful Attempt ◽  
Heart Of Darkness ◽  
The Rich ◽  
Collective Narrative

“Heart of Darkness” is a multilayered but coherent work whose universally acclaimed appeal draws on its thematic preoccupation with the problems of initiation and cognition. The rich variety of interpretations and creative reworks of the novella vary from discussions of its importance as a sample of anticolonial fiction to the acknowledgement of its role as a precursor to contemporary fantastic literature. The first Bulgarian dramatisation of “Heart of Darkness”, screen-written and directed by Valeria Valcheva, is an insightful and successful attempt to do justice to both its contents and the suggestive power of its poetics translated into the language of drama. The performance combines the stylistic features of farce, cabaret, ritual and classical theatre, inserting fragments of Edgar Allan Poe, Vachel Lindsay, Tom Waits, Thomas Eliot and even Pushkin’s poems. Valcheva is particularly concerned with reading Conrad’s work as a “European” collective narrative where the African Other is rendered through the poetic features of mask-wearing and the symbolic “curtain” of the jungle. The performance is likewise accompanied by music that includes the “talking drums” of Congo, and its stage design was apparently borrowed from Orson Welles’s cinematic adaptations. One of the outstanding contributions of the Bulgarian performance to the earlier attempts at dramatising Conrad’s work is the use of a marionette to represent Kurtz’s self-glorified condition. The play likewise foregrounds the biographical aspect of Conrad’s work related to Conrad and Marguerite Poradowska’s correspondence.

scholarly journals Bi3+ and Eu3+ Activated Luminescent Behaviors in Non-Stoichiometric LaO0.65F1.7 Structure

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2326
Author(s):  
Sungjun Yang ◽  
Sangmoon Park
Keyword(s):  
Optical Materials ◽  
Emission Spectra ◽  
Lattice Energy ◽  
Host Lattice ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Diffraction Patterns ◽  
Cation Sites

Optical materials composed of La1-p-qBipEuqO0.65F1.7 (p = 0.001–0.05, q = 0–0.1) were prepared via a solid-state reaction using La(Bi,Eu)2O3 and NH4F precursors at 1050 °C for two hours. X-ray diffraction patterns of the phosphors were obtained permitting the calculation of unit-cell parameters. The two La3+ cation sites were clearly distinguished by exploiting the photoluminescence excitation and emission spectra through Bi3+ and Eu3+ transitions in the non-stoichiometric host lattice. Energy transfer from Bi3+ to Eu3+ upon excitation with 286 nm radiation and its mechanism in the Bi3+- and Eu3+-doped host structures is discussed. The desired Commission Internationale de l’Eclairage values, including emissions in blue-green, white, and red wavelength regions, were obtained from the Bi3+- and Eu3+-doped LaO0.65F1.7 phosphors.

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