Structural Chemistry

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Peter D Battle - One of the best experts on this subject based on the ideXlab platform.

  • Structural Chemistry and magnetic properties of y2coge4o12
    2015
    Co-Authors: Xiao Qiang Liu, Peter D Battle, Joe Ridout, Silvia Ramos
    Abstract:

    Polycrystalline YCoGe4O12 is prepared by calcination of stoichiometric amounts of GeO2, Y2O3, and Co3O4 in air (1050 °C, ≈100 h).

  • Structural Chemistry and magnetic properties of y2coge4o12
    2015
    Co-Authors: Xiao Qiang Liu, Peter D Battle, Joe Ridout, Silvia Ramos
    Abstract:

    Abstract Polycrystalline Y2CoGe4O12 has been prepared by standard ceramic methods. The crystal structure (space group P4/nbm; a=9.8465(2), c=4.92986(9) A) consists of metal-rich layers separated from each other by Ge4O12 groups comprised of four corner-sharing GeO4 tetrahedra. Two cation sites lie within the layers; an eight-coordinate site occupied by yttrium and a six-coordinate site occupied by a 1:1 disordered distribution of yttrium and cobalt. Neutron diffraction revealed two-fold disorder on the oxide sublattice; this has been elucidated using Co K-edge EXAFS spectroscopy. The availability of two sites allows each oxide ion to accommodate the coordination preferences of its single Co/Y neighbour; the GeO4 tetrahedra distort to absorb any consequent strain. The octahedron of anions around each Co2+ cation shows a pseudo-tetragonal distortion with a strain (Co–O)eq–(Co–O)ax/(Co–O)eq=−0.173. This results in an unusually large effective magnetic moment of 6.05 µB per Co2+ cation.

  • Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
    2014
    Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian Stansfield
    Abstract:

    The title compounds are prepared by solid state reactions of Nd2O3 or La2O3, Fe2O3, M2O3 (M: Al, Ga, In), and excess Li2CO3 (alumina crucibles, 800 °C, 16 h).

  • Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
    2014
    Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian Stansfield
    Abstract:

    Abstract Polycrystalline samples of Nd18Li8Fe4M′O39 (M′=Al, Ga) and La18Li8Fe4.5In0.5O39 have been prepared by the ceramic method and characterised by neutron diffraction and magnetometry. All three compounds adopt a cubic structure (space group Pm 3 ¯ n, a ~12 A) based on intersecting 〈1 1 1〉 chains of cation sites with alternating octahedral and prismatic coordination geometry. These sites are occupied by Li, Fe and M′ or In; Nd or La cations occupy sites between the chains. The cation distribution over the octahedral and prismatic sites within the chains is disordered in all three compounds. The Nd-containing compositions show spin-glass behaviour below ~4.5 K whereas small, weakly-ferrimagnetic domains form in La18Li8Fe4.5In0.5O39 below 7.60 K. The dependence of the magnetic properties on the nature of the lanthanide cation is discussed.

  • Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
    2010
    Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji Nakanishi
    Abstract:

    The title compounds (0.5 ≤ x ≤ 5) are synthesized by solid state reactions of stoichiometric mixtures of the metal(III) oxides and a 50% excess of Li2CO3 (air, 800 °C, 12 h; 1000 °C, 1 h).

Nirawat Thammajak - One of the best experts on this subject based on the ideXlab platform.

  • Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
    2014
    Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian Stansfield
    Abstract:

    The title compounds are prepared by solid state reactions of Nd2O3 or La2O3, Fe2O3, M2O3 (M: Al, Ga, In), and excess Li2CO3 (alumina crucibles, 800 °C, 16 h).

  • Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
    2014
    Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian Stansfield
    Abstract:

    Abstract Polycrystalline samples of Nd18Li8Fe4M′O39 (M′=Al, Ga) and La18Li8Fe4.5In0.5O39 have been prepared by the ceramic method and characterised by neutron diffraction and magnetometry. All three compounds adopt a cubic structure (space group Pm 3 ¯ n, a ~12 A) based on intersecting 〈1 1 1〉 chains of cation sites with alternating octahedral and prismatic coordination geometry. These sites are occupied by Li, Fe and M′ or In; Nd or La cations occupy sites between the chains. The cation distribution over the octahedral and prismatic sites within the chains is disordered in all three compounds. The Nd-containing compositions show spin-glass behaviour below ~4.5 K whereas small, weakly-ferrimagnetic domains form in La18Li8Fe4.5In0.5O39 below 7.60 K. The dependence of the magnetic properties on the nature of the lanthanide cation is discussed.

  • Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
    2010
    Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji Nakanishi
    Abstract:

    The title compounds (0.5 ≤ x ≤ 5) are synthesized by solid state reactions of stoichiometric mixtures of the metal(III) oxides and a 50% excess of Li2CO3 (air, 800 °C, 12 h; 1000 °C, 1 h).

  • Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
    2010
    Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji Nakanishi
    Abstract:

    Polycrystalline samples of Ln18Li8Rh5−xFexO39 (Ln = La, Nd; 0.5 ≤ x ≤ 5) have been synthesized by a solid-state method and studied by a combination of dc and ac magnetometry, neutron diffraction, and Mossbauer spectroscopy. All compositions adopt a cubic structure (space group Pm3n, a0 ∼ 12 A) based on intersecting ⟨111⟩ chains made up of alternating octahedral and trigonal-prismatic coordination sites. These chains occupy channels within a Ln−O framework. At low values of x, iron preferentially occupies the smaller (2a) of the two distinct octahedral sites as low-spin Fe(IV). The Rh(III) on the larger (8e) octahedral site is replaced by high-spin Fe(III). Nd-containing compositions having x > 1 show spin-glass-like behavior below ∼5 K. La-containing compositions having x > 1 show evidence of a magnetic transition at ∼8 K, but the nature of the transition is unclear. This contrasting behavior demonstrates that, although the Structural Chemistry of the two systems is essentially the same, the magnetic cha...

Rhian Stansfield - One of the best experts on this subject based on the ideXlab platform.

  • Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
    2014
    Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian Stansfield
    Abstract:

    The title compounds are prepared by solid state reactions of Nd2O3 or La2O3, Fe2O3, M2O3 (M: Al, Ga, In), and excess Li2CO3 (alumina crucibles, 800 °C, 16 h).

  • Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
    2014
    Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian Stansfield
    Abstract:

    Abstract Polycrystalline samples of Nd18Li8Fe4M′O39 (M′=Al, Ga) and La18Li8Fe4.5In0.5O39 have been prepared by the ceramic method and characterised by neutron diffraction and magnetometry. All three compounds adopt a cubic structure (space group Pm 3 ¯ n, a ~12 A) based on intersecting 〈1 1 1〉 chains of cation sites with alternating octahedral and prismatic coordination geometry. These sites are occupied by Li, Fe and M′ or In; Nd or La cations occupy sites between the chains. The cation distribution over the octahedral and prismatic sites within the chains is disordered in all three compounds. The Nd-containing compositions show spin-glass behaviour below ~4.5 K whereas small, weakly-ferrimagnetic domains form in La18Li8Fe4.5In0.5O39 below 7.60 K. The dependence of the magnetic properties on the nature of the lanthanide cation is discussed.

Shinji Nakanishi - One of the best experts on this subject based on the ideXlab platform.

  • Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
    2010
    Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji Nakanishi
    Abstract:

    The title compounds (0.5 ≤ x ≤ 5) are synthesized by solid state reactions of stoichiometric mixtures of the metal(III) oxides and a 50% excess of Li2CO3 (air, 800 °C, 12 h; 1000 °C, 1 h).

  • Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
    2010
    Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji Nakanishi
    Abstract:

    Polycrystalline samples of Ln18Li8Rh5−xFexO39 (Ln = La, Nd; 0.5 ≤ x ≤ 5) have been synthesized by a solid-state method and studied by a combination of dc and ac magnetometry, neutron diffraction, and Mossbauer spectroscopy. All compositions adopt a cubic structure (space group Pm3n, a0 ∼ 12 A) based on intersecting ⟨111⟩ chains made up of alternating octahedral and trigonal-prismatic coordination sites. These chains occupy channels within a Ln−O framework. At low values of x, iron preferentially occupies the smaller (2a) of the two distinct octahedral sites as low-spin Fe(IV). The Rh(III) on the larger (8e) octahedral site is replaced by high-spin Fe(III). Nd-containing compositions having x > 1 show spin-glass-like behavior below ∼5 K. La-containing compositions having x > 1 show evidence of a magnetic transition at ∼8 K, but the nature of the transition is unclear. This contrasting behavior demonstrates that, although the Structural Chemistry of the two systems is essentially the same, the magnetic cha...

R Guedj - One of the best experts on this subject based on the ideXlab platform.