Ferrimagnetism as a Consequence of Unusual Cation Ordering in the Perovskite SrLaFeCoSbO.

A polycrystalline sample of SrLaFeCoSbO has been prepared in a solid-state reaction and studied by a combination of electron microscopy, magnetometry, Mössbauer spectroscopy, X-ray diffraction, and neutron diffraction. The compound adopts a monoclinic (space group P2/ n; a = 5.6218(6), b = 5.

Magnetic properties of LnCoGeO and LnBCoGeO (Ln = Gd, Tb, Dy, Ho, Er; B = Sc, Lu).

Polycrystalline samples of LnCoGeO (Ln = Gd, Tb, Dy, Ho or Er) and LnBCoGeO (B = Sc or Lu) have been prepared and characterised by a combination of magnetometry, Gd Mössbauer spectroscopy and, in the case of TbCoGeO and TbScCoGeO, neutron diffraction. The holmium- and erbium-containing compositions remain paramagnetic down to 2 K, those containing dysprosium behave as spin glasses and the terbium and gadolinium-containing compounds show long-range magnetic order with transition temperatures below 4 K in all cases. The data can be rationalized qualitatively in terms of the interplay between magnetic anisotropy and crystal field effects.

Experimental and computational study of the magnetic properties of ZrMnCoGeO.

Polycrystalline samples in the solid solution ZrMnCoGeO (x = 0.0, 0.5, 1.

Magnetic Properties of CeMnCoGeO (0 ≤ x ≤ 2) as a Function of Temperature and Magnetic Field.

Polycrystalline samples, prepared by a solid-state route, of compositions in the solid solution CeMnCoGeO (x = 0.0, 0.5, 1.

Dimer-mediated cation diffusion in the stoichiometric ionic conductor Li3N.

Non-equilibrium molecular dynamics has been used to model cation diffusion in stoichiometric Li3N over the temperature range 50 < T/K < 800. The resulting diffusion coefficients are in excellent agreement with the available experimental data. We present a detailed atomistic account of the diffusion process.

Diffusion in Li₂O studied by non-equilibrium molecular dynamics for 873 < T/K < 1603.

The use of non-equilibrium molecular dynamics facilitates the calculation of the cation diffusion constant of Li2O at temperatures too low to be accessible by other methods. Excellent agreement with experimental diffusion coefficients has been obtained over the temperature range 873 < T/K < 1603. Diffusion below 1200 K was shown to be dominated by a concerted nearest-neighbour hopping process, whereas in the high-temperature superionic region an additional mechanism involving a six-coordinate interstitial cation site in the anti-fluorite structure becomes increasingly dominant.

La3Ni2SbO9: a relaxor ferromagnet.

A polycrystalline sample of La3Ni2SbO9 has been synthesized using a standard ceramic method and characterized by neutron diffraction and magnetometry. The compound adopts a monoclinic, perovskite-like structure with space group P2(1)/n and unit cell parameters a = 5.0675(1), b = 5.

Li11Nd18Fe4O(39-δ) revisited.

The structure proposed for Li(11)Nd(18)Fe(4)O(39-δ) (Chen et al. Inorg. Chem.

Structural chemistry and magnetic properties of Ln18Li8Rh(5-x)Fe(x)O39 (Ln = La, Nd).

Polycrystalline samples of Ln(18)Li(8)Rh(5-x)Fe(x)O(39) (Ln = La, Nd; 0.5 < or = x < or = 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, a(0) approximately 12 A) based on intersecting 111 chains made up of alternating octahedral and trigonal-prismatic coordination sites.

Magnetic ordering in nitrides with the eta-carbide structure, (Ni,Co,Fe)2(Ga,Ge)Mo3N.

Compositions in the series Ni(2-x)Co(x)GeMo(3)N (0 < or = x < or = 2), Co(2)Ge(1-x)Ga(x)Mo(3)N (0 < x < or = 0.7), Co(2-x)Fe(x)GeMo(3)N (0 < or = x < or = 2), and Co(2-x)Fe(x)Ge(0.5)Ga(0.

Use of in situ neutron diffraction to monitor high-temperature, solid/H2-gas reactions.

For the first time, the chemistry in H(2) gas of a perovskite-like material, Pr(2)Sr(2)CrNiO(8), has been monitored at temperatures up to approximately 700 degrees C, in situ, by neutron powder diffraction.

Structural chemistry and magnetic properties of Nd18Li8Fe(5-x)M(x)O39 (M = Mn, Co).

Polycrystalline samples of Nd(18)Li(8)Fe(5-x)M(x)O(39) (M = Mn, 0 < x < or = 4; M = Co; 0 < x < or = 3) have been synthesized using a solid-state method and have been studied using a combination of dc and ac magnetometry, neutron diffraction, and Mössbauer spectroscopy. All compositions adopt a cubic structure (space group Pm3n, a(0) approximately 11.9 A) based on intersecting <111> chains made up of alternating octahedral and trigonal-prismatic coordination sites.

Structural chemistry and magnetic properties of Nd18Li8Fe5O39 and Nd18Li8Co4O39: the interplay of cation and spin ordering.

Polycrystalline samples of Nd(18)Li(8)Fe(5)O(39) and Nd(18)Li(8)Co(4)O(39) have been synthesized using a solid-state method and studied by a combination of neutron diffraction, direct and alternating current magnetometry, and, in the case of Nd(18)Li(8)Fe(5)O(39), Mossbauer spectroscopy. Both compounds adopt a cubic structure (space group Pm3n, a(0) approximately 11.9 A) based on intersecting 111 chains made up of alternating octahedral and trigonal-prismatic coordination sites.

Ln18Li8Rh5O39 (Ln = La, Pr): a mixed-metal oxide with a charge-ordered arrangement of Rh3+ and Rh4+.

Polycrystalline samples of Ln18Li8Rh5O39 (Ln = La, Pr) have been synthesized by the ceramic method and characterized by X-ray and neutron diffraction. The compounds crystallize in the cubic space group Pmn, with a0 approximately 12.1 Angstroms.

Structural chemistry of A3CuBO6 (A = Ca, Sr; B = Mn, Ru, Ir) as a function of temperature.

Variable temperature X-ray and neutron powder diffraction techniques have been used to identify structural phase transitions in Cu-rich A(3)A'BO(6) phases. A transition from monoclinic to rhombohedral symmetry was observed by X-ray diffraction between 700 and 500 K in Sr(3)Cu(1-x)M(x)IrO(6) (M = Ni, Zn; 0 < or = x < or = 0.5).

The observation of magnetic excitations in a single layered and a bilayered brownmillerite.

We describe the results of an inelastic neutron scattering measurement of the magnetic excitations in SrCaGaMnO(5+δ), a quasi-two-dimensional compound whose structure consists of layers of MnO(6) octahedra separated by layers of GaO(4) tetrahedra (the brownmillerite structure), and Ca(2.5)Sr(0.5)Mn(2)GaO(8), a bilayered brownmillerite.

Ca(2.5)Sr(0.5)GaMn2O8: diamagnetic Ga in control of the structural and electronic properties of a bilayered manganate.

The temperature dependence of the crystal structure and electronic properties of brownmillerite-like Ca(2.5)Sr(0.5)GaMn(2)O(8) has been studied by neutron powder diffraction and muSR spectroscopy.

The prediction of inorganic crystal framework structures using excluded regions within a genetic algorithm approach.

We have developed a new technique, which is complementary to other procedures, that will have wide applicability for generating new feasible framework structures with defined microporous architectures from the knowledge of only the unit cell dimensions, constituent elements and by defining forbidden regions within the unit cell.

Magnetism and structural chemistry of the n = 1 Ruddlesden-Popper phases La4LiMnO8 and La3SrLiMnO8.

Polycrystalline samples of La4LiMnO8 and La3SrLiMnO8 have been studied by a combination of X-ray diffraction (XRD), neutron diffraction (ND), 6Li MAS NMR, electron microscopy (EM), and magnetometry. Room-temperature XRD and ND measurements suggest that both compounds have the K2NiF4 structure, with a disordered arrangement of Li and Mn over the six-coordinate sites. However, MAS NMR and EM demonstrate the presence of local 1:1 Li:Mn order on these sites, and EM shows that although cation order is well-developed in each xy sheet of corner-sharing octahedra, the sheets are stacked randomly along z.

15R SrMn(1-)(x)()Fe(x)()O(3)(-)(delta) (x approximately 0.1); A New Perovskite Stacking Sequence.

A polycrystalline sample of a new phase in the Sr-Fe-Mn-O system has been prepared by standard solid-state techniques. Characterization at room temperature by X-ray diffraction, high-resolution electron microscopy, Mössbauer spectroscopy and neutron diffraction has led to it being described as a 15-layered, rhombohedral (15R) perovskite [space group R&thremacr;m: a = 5.4489(1) Å, c = 33.