Lateral twin boundaries in spinel

Carter, C. B.; Elgat, Z.; Shaw, T. M.

doi:10.1080/01418618708209798

Cited by 19 publications

(5 citation statements)

References 7 publications

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“…The structure is shown in Fig. 3, type B, which was proposed earlier in literature [3]. However, "nonstoichiometric" boundaries with like cation layers as in Mg0.2A1203 [3] were not observed in our study.…”

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confidence: 70%

Interfaces between MgA1₂O₄ Spinel Layers and Oxide Substrates

Boese

Mader

2003

Microsc Microanal

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Interfaces including A1203 (sapphire, S) and MgAlzOa (spinel, SP) have been object of some investigations, in particular in topotaxial systems. However, details concerning the interfacial structure have rarely been reported. In our study thin films of MgA1204 spinel on basal lane sapphire were prepared by chemical solution deposition (CSD). A precursor solution, containing Al(N03)3 and Mg(N03)2 is deposited on the substrates. Optimum conditions for heteroepitaxial growth are achieved by a 4h heat treatment at 1250°C. X-ray and electron diffraction prove epitactixial growth of the spinel phase on the sapphire substrate. The orientation relationship is

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confidence: 70%

Interfaces between MgA1₂O₄ Spinel Layers and Oxide Substrates

Boese

Mader

2003

Microsc Microanal

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“…Spinels are known to form complicated twin structures 20 , which lead to stacking faults of the <111> planes. Such faults have been observed in MgAl 2 O 4 by transmission electron microscopy (TEM) 19 . Starting from the ideal spinel structure shown in Fig.…”

Section: Discussionmentioning

confidence: 88%

Unconventional magnetic order in the frustrated diamond-lattice antiferromagnetCoAl2O4studied by neutron diffraction and classical Monte Carlo simulation

et al. 2014

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CoAl 2 O 4 spinel with magnetic Co 2+ ions on the diamond lattice is known to be magnetically frustrated. We compare neutron single-crystal diffraction patterns measured in zero and applied magnetic fields with the ones obtained from classical Monte Carlo models. In simulations we test the influence of various parameters on diffraction patterns: the ratio of nearest-, J 1 , and next-nearest-, J 2 , neighbor interactions, magnetic field applied along the principal crystallographic directions, and random disorder on the A(Co 2+ ) and B(Al 3+ ) sites. We conclude that the models considered so far explain the broadening of magnetic Bragg peaks in zero magnetic field and their anisotropic response to applied magnetic field only partly. As bulk properties of our single crystal are isotropic, we suggest that its microstructure, specifically 111 -twin boundaries, could be a reason for the nonconventional magnetic order in CoAl 2 O 4 .

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“…It will be important to study the microstructure in the LT phase and its consequence on the magnetic orders by means of electron transmission microscopy. It is well documented 32,33 that spinels, besides the inver-sion, have tendency for complicated grain and twin boundaries with dislocations and cation rearrangement and the variations of the HT/LT structural transition might germinate from these effects.…”

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confidence: 99%

Manifolds of magnetic ordered states and excitations in the almost Heisenberg pyrochlore antiferromagnet MgCr2O4

et al. 2018

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In spinels ACr 2 O 4 (A=Mg, Zn) realisation of the classical pyrochlore Heisenberg antiferromagnet model is complicated by a strong spin-lattice coupling: the extensive degeneracy of the ground state is lifted by a magneto-structural transition at T N =12.5 K. We study the resulting low-temperature low-symmetry crystal structure by synchrotron x-ray diffraction. The consistent features of x-ray low-temperature patterns are explained by the tetragonal model of Ehrenberg et. al [Pow. Diff. 17, 230( 2002)], while other features depend on sample or cooling protocol. Complex partially ordered magnetic state is studied by neutron diffraction and spherical neutron polarimetry. Multiple magnetic domains of configuration arms of the propagation vectors k 1 =( 1 2 1 2 0), k 2 =(1 0 1 2 ) appear. The ordered moment reaches 1.94(3) µ B /Cr 3+ for k 1 and 2.08(3)µ B /Cr 3+ for k 2 , if equal amount of the k 1 and k 2 phases is assumed. The magnetic arrangements have the dominant components along the [110] and [1-10] diagonals and a smaller c-component. By inelastic neutron scattering we investigate the spin excitations, which comprise a mixture of dispersive spin waves propagating from the magnetic Bragg peaks and resonance modes centered at equal energy steps of 4.5 meV. We interpret these as acoustic and optical spin wave branches, but show that the neutron scattering cross sections of transitions within a unit of two corner-sharing tetrahedra match the observed intensity distribution of the resonances. The distinctive fingerprint of cluster-like excitations in the optical spin wave branches suggests that propagating excitations are localized by the complex crystal structure and magnetic orders.3

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Lateral twin boundaries in spinel

Cited by 19 publications

References 7 publications

Interfaces between MgA1₂O₄ Spinel Layers and Oxide Substrates

Interfaces between MgA1₂O₄ Spinel Layers and Oxide Substrates

Unconventional magnetic order in the frustrated diamond-lattice antiferromagnetCoAl2O4studied by neutron diffraction and classical Monte Carlo simulation

Manifolds of magnetic ordered states and excitations in the almost Heisenberg pyrochlore antiferromagnet MgCr2O4

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Lateral twin boundaries in spinel

Cited by 19 publications

References 7 publications

Interfaces between MgA12O4 Spinel Layers and Oxide Substrates

Interfaces between MgA12O4 Spinel Layers and Oxide Substrates

Unconventional magnetic order in the frustrated diamond-lattice antiferromagnetCoAl2O4studied by neutron diffraction and classical Monte Carlo simulation

Manifolds of magnetic ordered states and excitations in the almost Heisenberg pyrochlore antiferromagnet MgCr2O4

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Interfaces between MgA1₂O₄ Spinel Layers and Oxide Substrates

Interfaces between MgA1₂O₄ Spinel Layers and Oxide Substrates