J. Rodríguez-Carvajal

Recent advances in magnetic structure determination by neutron powder diffraction

Abstract In spite of intrinsic limitations, neutron powder diffraction is, and will still be in the future, the primary and most straightforward technique for magnetic structure determination. In this paper some recent improvements in the analysis of magnetic neutron powder diffraction data are discussed. After an introduction to the subject, the main formulas governing the analysis of the Bragg magnetic scattering are summarized and shortly discussed. Next, we discuss the method of profile fitting without a structural model to get precise integrated intensities and refine the propagation vector(s) of the magnetic structure. The simulated annealing approach for magnetic structure determination is briefly discussed and, finally, some features of the program FullProf concerning the magnetic structure refinement are presented and discussed. The different themes are illustrated with simple examples.

Neutron diffraction study on structural and magnetic properties of La2NiO4

An overall survey of the structural and magnetic features of the La2NiO4+ delta system is presented as a result of neutron diffraction experiments. The stoichiometric compound ( delta =0) presents two structural phase transitions. At T0 approximately=770 K, La2NiO4 transforms from tetragonal (I4/mmm) to orthorhombic (Bmab); at T1 approximately=80 K, from orthorhombic to a new tetragonal (P42/ncm) phase. Associated with this second phase transition a strong microstrain produces anisotropic broadening of Bragg reflections. La2NiO4 is three-dimensional (3D) antiferromagnetically ordered at room temperature (TN=330 K). A weak ferromagnetic component appears below T1. Oxygen excess suppress the 3D magnetic ordering and the structural phase transformations, giving rise to a non-stoichiometric compound with interstitial oxygens. A tentative phase diagram is proposed.

Structural characterization of R2BaCuO5 (R = Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Eu and Sm) oxides by X-ray and neutron diffraction

Abstract R2BaCuO5 compounds with R = rare earth atom from Sm to Lu have been studied by neutron and X-ray powder diffraction. All of them are isostructural, and belong to the space group Pnma (Z = 4). A comparative study of the influence of the rare earth size on the structural parameters is presented. The stability of the structure is estimated from the agreement between valence bond sums and formal valence states. A systematic variation of the structural stability is found depending on the size of the rare earth atom.

Liquidlike Spatial Distribution of Magnetic Droplets Revealed by Neutron Scattering in La 1 − x Ca x MnO 3

Elastic neutron scattering experiments, performed in semiconducting

Cation distribution and intrinsic magnetic properties of Co‐Ti‐doped M‐type barium ferrite

{\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}

The Role of Order-Disorder Transitions in the Quest for Molecular Multiferroics: Structural and Magnetic Neutron Studies of a Mixed Valence Iron (II)-Iron (III) Formate Framework

single crystals

The effects of moderate thermal treatments under air on LiFePO 4-based nano powders

(x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.05,0.08)

Oxygen excess and superconductivity at 45 K in La2CaCu2O6+y

, reveal new features in the problem of electronic phase separation and metal insulator transition. Below

Structural studies of LaNi4CoD6.11 and LaNi3.55Mn0.4Al0.3Co0.75D5.57 by means of neutron powder diffraction

{T}_{N}

Surface spin canting in BaFe12O19 fine particles

, the observation of a broad magnetic modulation in the