Crystallographic and Magnetic properties of the systems lithium ferrite-aluminate and lithium ferrite-gallate

Schulkes, J.A.; Blasse, G.

doi:10.1016/0022-3697(63)90110-0

Cited by 74 publications

(11 citation statements)

References 14 publications

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“…Miles [13], Caster et al [14], Waxwell and Pickert [15] Schulkes and Blasse [16], Maria et al [17], Widataulah et al [8], and George et al [18] have studied Li-Al ferrites for their electrical and magnetic properties. Jung et al [19] studied ion distribution in a series of Al 3+ doped lithium ferrite.…”

Section: Introductionmentioning

confidence: 97%

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Dar

Batoo

Verma

et al. 2010

Journal of Alloys and Compounds

212

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Section: Introductionmentioning

confidence: 97%

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Dar

Batoo

Verma

et al. 2010

Journal of Alloys and Compounds

212

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“…1) is conclusive evidence of cation order, the ordered structures have not been isolated as single phases under the present experimental conditions. When spherically symmetric ions such as Ga 3+ or Al 3+ are substituted in lithium ferrite, long-range order is retained [12], which suggests that the disorder in the Cr substituted compounds probably arises because of the large octahedral site stabilization energy of Cr 3+ . On the basis of site stabilization alone Mn 3+ ion should be least effective in removing of order, however being a Jahn-Teller ion it also creates localized distortions in the structure (the formation of Mn 3+ ion clusters) [12].…”

Section: Resultsmentioning

confidence: 99%

Characterization of Structural Properties of LiM_xFe_5-xO₈(M=Al, Cr, Mn) Spinel Solid Solutions

Darul

2008

Acta Phys. Pol. A

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The structural properties of series spinel oxides with the general formula, LiM 0.5 Fe 4.5 O 8 (M = Mn, Cr, Al), are investigated. The effect of limited substitution of manganese, chromium and aluminum ions in the lithium ferrite samples on the order-disorder phase transition in the spinel crystal lattice at room temperature is presented. In these materials it is found that the ordered structures have not been isolated as single phases under the present experimental conditions and this fact will certainly influence the magnetic behavior of the compounds. The Rietveld refinements of the synchrotron X-ray diffraction data revealed that transition metal ions hinders the ordering process and Al 3+ ion was shown to be least effective in removing of order.

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“…As antiphase domains in unsubstituted lithium ferrite have a rapid rate of growth once the temperature drops below the transition value (Cheary & Grimes, 1978), the retention of these domains in the present substituted specimens, and not in the unsubstituted specimen, must be directly attributable to the Cr 3+ ions. When spherically symmetric ions such as Ga 3+ or Al 3+ are substituted in lithium ferrite, longrange order is retained (Shulkes & Blasse, 1963) which suggests that the disorder in the Cr substituted compounds probably arises because of the large octahedral site stabilization energy of Cr a+ ions (McClure, 1957). This could act to reduce the mobility of the Cr 3+ ions between octahedral sites relative to Fe 3+ ions so that the domain growth rate, which is governed by the migration of the ions at the domain boundaries, is also reduced.…”

Section: Analysis and Discussion Of Resultsmentioning

confidence: 99%

An X-ray diffraction investigation of chromium-substituted lithium ferrite

Cheary¹,

Grimes²

1979

Acta Cryst Sect A

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The loss of order in the lithium spinel system Fe(Li0.sFel.5_~/sCrx/8)O 4 with 0 < x < 2 is examined as a function of the Cr 3÷ ion concentration through an analysis of the X-ray superlattice line integrated intensities and line breadths. In these materials it is found that the growth of the antiphase domains is inhibited by the action of Cr 3÷ ions at the domain boundaries and it is shown that the observed variation of the long-range order parameter may be explained on the basis of a cation distribution on the octahedral sites which adheres to the so-called tetrahedral invariance condition. Furthermore, a correlation exists between the probability of an unstable Cr 3÷ ion configuration and the formation of domain boundaries. Some discussion is presented on the variation of the domain thickness distribution with Cr 3÷ ion content. IntroductionLithium spinels of the type M3+(Li0.sMla.+)O4, M corresponding to Fe, AI or Ga, possess an ordered structure on the octahedrally coordinated sites which is described by the cubic space group P4332 or its enantiomorph P4t32 (Braun, 1952). The stability of the ordered arrangement arises principally because each Li + ion has only M 3+ ions as nearest-neighbour octahedral ions. This configuration is referred to as tetrahedral charge invariance (Anderson, 1956) as it is equivalent to each tetrahedral group of octahedral ions comprising one Li ÷ ion and three M 3÷ ions. For lithium ferrite this form of short-range order is rigidly adhered to in the disordered structure above 1008 K (Brunel & de Bergevin, 1966) and in the partially ordered structure immediately below this temperature (Cheary & Grimes, 1978).When transition-metal ions with a large octahedral site stabilisation energy are substituted on the octahedral sites, the structure gradually reverts to the statistically face-centred form (space group Fd3m) 0567-7394/79/040665-08501.00 normally associated with spinel compounds (Gorter, 1954;Blasse, 1964;Rogers, Germann & Arnott, 1965). This is indicated by the disappearance of the superlattice lines in the X-ray diffraction pattern. For Cr 3+ or Rh 3+ ions the critical concentration is approximately four substituted ions per unit cell, but with Mn 3+ ions it is only two ions per unit cell. In these materials the site stabilization energy of the ions hinders the ordering process to the extent that at the critical concentration it is the dominant factor in determining the distribution of the transition-metal ions. On the basis of site stabilization energy alone the Mn 3÷ ion should be least effective in removing the order; however, being a Jahn-Teller ion it also creates localized distortions in the structure (Rogers, Germann & Arnott, 1965). The latter are made manifest through anomalies in the compositional dependence of the lattice parameter which arise, it is believed, from the formation of Mn 3÷ ion clusters. It is worth remarking that the squareness of the magnetic hysteresis loop in the system Fe(Lio. 5 Fe~. 5 _ x/sMnx:8)O4 is optimized for substitutions x between...

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Crystallographic and Magnetic properties of the systems lithium ferrite-aluminate and lithium ferrite-gallate

Cited by 74 publications

References 14 publications

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Characterization of Structural Properties of LiM_xFe_5-xO₈(M=Al, Cr, Mn) Spinel Solid Solutions

An X-ray diffraction investigation of chromium-substituted lithium ferrite

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Crystallographic and Magnetic properties of the systems lithium ferrite-aluminate and lithium ferrite-gallate

Cited by 74 publications

References 14 publications

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Synthesis and characterization of nano-sized pure and Al-doped lithium ferrite having high value of dielectric constant

Characterization of Structural Properties of LiMxFe5-xO8(M=Al, Cr, Mn) Spinel Solid Solutions

An X-ray diffraction investigation of chromium-substituted lithium ferrite

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Characterization of Structural Properties of LiM_xFe_5-xO₈(M=Al, Cr, Mn) Spinel Solid Solutions