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Peter D Battle - One of the best experts on this subject based on the ideXlab platform.
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Structural Chemistry and magnetic properties of y2coge4o12
2015Co-Authors: Xiao Qiang Liu, Peter D Battle, Joe Ridout, Silvia RamosAbstract:Polycrystalline YCoGe4O12 is prepared by calcination of stoichiometric amounts of GeO2, Y2O3, and Co3O4 in air (1050 °C, ≈100 h).
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Structural Chemistry and magnetic properties of y2coge4o12
2015Co-Authors: Xiao Qiang Liu, Peter D Battle, Joe Ridout, Silvia RamosAbstract: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.
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Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
2014Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian StansfieldAbstract: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).
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Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
2014Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian StansfieldAbstract: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.
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Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
2010Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji NakanishiAbstract: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.
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Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
2014Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian StansfieldAbstract: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).
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Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
2014Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian StansfieldAbstract: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.
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Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
2010Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji NakanishiAbstract: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).
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Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
2010Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji NakanishiAbstract: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.
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Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
2014Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian StansfieldAbstract: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).
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Structural Chemistry and magnetic properties of nd18li8fe4m o39 m al ga and la18li8fe4 5in0 5o39
2014Co-Authors: Nirawat Thammajak, Peter D Battle, Catherine Brown, Katherine Higgon, Rhian StansfieldAbstract: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.
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Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
2010Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji NakanishiAbstract: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).
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Structural Chemistry and magnetic properties of ln18li8rh5 xfexo39 ln la nd
2010Co-Authors: Peter D Battle, Siân E Dutton, Nirawat Thammajak, Fernande Grandjean, Moulay Tahar Sougrati, Gary J Long, Katsuyoshi Ohishi, Shinji NakanishiAbstract: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.
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fluorinated amino acids and peptides synthesis of 3 3 difluoro 2 amino acids peptides and cyclodipeptides incorporating 3 3 difluoro 2 aminobutyric acid or 3 3 difluorophenylalanine residues in their structures
1991Co-Authors: M L Martosalcaniz, Roger Condom, P R T Frogier, R GuedjAbstract:Abstract Convenient syntheses have been developed for N -9-fluorenylmethyloxycarbonyl-DL-2-amino-3,3-difluoro-butanoic acid and N -9-fluorenylmethyloxycarbonyl-DL-3,3-difluorophenylalanine which have been successfully introduced into peptide syntheses. Several fluorinated peptides have been obtained either by active ester coupling methods, mixed anhydride synthesis or with the aid of dicyclohexylcarbodiimide (DCC) in presence of 1-hydroxybenzotriazole (HOBt). The method has been applied to the preparation of seven hitherto unpublished representative 3-(1,1′-difluoroalkyl)-2,5-dioxopiperazines for biological purposes and Structural Chemistry studies.