Spectroscopic determination of the distribution of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Cr</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>sites in mullite ceramics

Liu, Huimin; Knutson, Robert; Jia, Wei; Strauss, E.; Yen, W. M.

doi:10.1103/physrevb.41.12888

Cited by 10 publications

(8 citation statements)

References 6 publications

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“…In this case the staggered magnetization depends solely on the ratio of interplanar to planar coupling strength. For this condition the zero temperature staggered magnetization ðMð0ÞÞ is calculated to be 0.308 which is in fair agreement with the results ðMð0Þ ¼ 0:30Þ obtained by Liu [7] and Anderson [20,21].…”

Section: Resultssupporting

confidence: 87%

“…It is also observed that the exchange and dipolar anisotropies do not produce any measurable effect on the specific heat. Further, in the absence of dipolar anisotropy our expression (23) for the magnetic contribution to specific heat reduces to the result as obtained by Liu [7].…”

Section: Resultssupporting

confidence: 57%

“…The magnetic dynamics of the single layer systems has extensively been studied by various workers [1][2][3][4]. The studies are mainly based on treating the Heisenberg exchange Hamiltonian within random phase approximation (RPA), linear, nonlinear and the modified spinwave theory, Callen's and the Schwinger-Boson approach [5][6][7][8][9][10][11][12][13][14][15][16]. It has been pointed out [5,8] that the weak c-direction exchange coupling (J ? )…”

Section: Introductionmentioning

confidence: 99%

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Role of Dipole-Dipole Interaction on the Magnetic Dynamics of Anisotropic Layered Cuprate Antiferromagnets

Sharma

Govind

Pratap

et al. 2001

phys. stat. sol. (b)

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In the present paper, we report the role of dipole-dipole interaction on the magnetic dynamics of single layer antiferromagnets. For this, the model Hamiltonian includes the exchange Heisenberg Hamiltonian as well as dipole-dipole interactions. Within the linear spin-wave theory, we employ the double time Green's function technique to obtain expressions for the spin wave dispersion, sublattice magnetization and the magnetic contribution to specific heat as a function of various parameters of the model Hamiltonian. We observe through numerical calculations that in the absence of anisotropy in exchange couplings the dipole-dipole interaction works as an anisotropy and sustains the magnetization even in a pure 2D system.

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Section: Resultssupporting

confidence: 87%

Section: Resultssupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Role of Dipole-Dipole Interaction on the Magnetic Dynamics of Anisotropic Layered Cuprate Antiferromagnets

Sharma

Govind

Pratap

et al. 2001

phys. stat. sol. (b)

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“…Cr 3+ cation is expected to substitute Al 3+ in AlO 6 octahedra. However spectroscopic analyses suggested that Cr 3+ cation could also be distributed on distorted octahedral interstitial positions outside of AlO 6 octahedra [17,18]. Rossouw and Miller [19] studied the X-ray emission spectra of Cr 2 O 3 doped mullite and came to the conclusion that Cr 3+ was most probably located in the octahedral interstitial sites at (0, 0.25, 0).…”

Section: Géis Bifásicos Dementioning

confidence: 99%

Role of Cr2O3 on the mullittization of di-phasic Al2O3-SiO2 gel

Roy¹,

Bandyopadhyay

Das

et al. 2010

Cerâmica

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Diphasic Al2O3-SiO2 gel was synthesized by sol-gel route from inorganic salts following aqueous phase colloidal interaction and the effect of Cr2O3 additive on the formation of mullite ceramics from this diphasic gel was investigated. The gel powder was thoroughly characterized by chemical analysis, measurement of surface area, bulk density and FTIR spectroscopy. The calcined gel was compacted with Cr2O3 additives in three different proportions (ca. 1, 2 and 3 wt%) and heat treated at different elevated temperatures (ca, 1400, 1500 and 1600 ºC). The analyses of microstructure and phase composition of the sintered masses were carried out by scanning electron microscopy and XRD technique. The morphology of the mullite crystals changed significantly in the presence of the additives. It has been observed that more than 7% more mullite has been formed with the addition of maximum 3% additive only. Using the additive, the maximum reduction in apparent porosity was about 30% and maximum improvement in density in the sintered compacts was about 14%. The flexural strength and fracture toughness of the sintered compacts also improved by 16% and 6% respectively in the presence of the Cr2O3 additive under the experimental condition.

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“…Cr 3C cation should be expected to prefer an octahedral coordination, substituting for Al 3C in AlO 6 octahedra. However, spectroscopic analyses done by Knutson et al [8] and Liu et al [9] suggest that Cr 3C cations could be also distributed on distorted octahedral interstitial positions outside of AlO 6 octahedron. Rager et al [10] prepared mullite containing up to 12 wt% Cr 2 O 3 from oxide powder mixtures by means of a solidstate sintering.…”

Section: Introductionmentioning

confidence: 97%