CaMn0.96Mo0.04O3 is an example of Mn4+ rich perovskite manganites, which exhibits a net ferromagnetic component at low temperature, observed by dc magnetization and ac susceptibility. To characterize the magnetic state of this compound, neutron powder diffraction was carried out in the 2–400K temperature range, showing that it is necessary to use three components (ferromagnetic and G- and A-type antiferromagnetic) to describe it. This particular state is in agreement with the unusual magnetic behaviour observed by macroscopic measurements and is compared to the one observed for manganites with similar Mn valence but obtained by A-site substitution.

The structural and physical properties of the electron-doped ${\mathrm{Sm}}_{0.1}{\mathrm{Ca}}_{0.9\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Mn}{\mathrm{O}}_{3}$ perovskite manganites $(0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.8)$ have been studied by combining x-ray and neutron diffractions with measurements of magnetization (in static or pulsed magnetic fields), magnetic susceptibility, and resistivity. A structural change, from $Pnma$ (for $x\ensuremath{\leqslant}0.4$) to $I4∕mcm$ $(0.5\ensuremath{\leqslant}x<0.8)$, is observed at room temperature. A detailed study of two compounds ($x=0.3$ and 0.6), belonging to each structural region, demonstrates different phase separations at low temperature, with mixtures of $C$- and $G$-type antiferromagnetisms associated with different crystallographic structures ($P{2}_{1}∕m$ for $x=0.3$ and $I4∕mcm$ for $x=0.6$). The stabilization of different (crystallographic and magnetic) states together with the different N\'eel temperatures gives the opportunity to control the robustness of the antiferromagnetism versus $A$-site size parameters, such as $⟨{r}_{A}⟩$ and ${\ensuremath{\sigma}}^{2}$. Since $50\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ are not sufficient to collapse the antiferromagnetism in ${\mathrm{Sm}}_{0.1}{\mathrm{Ca}}_{0.3}{\mathrm{Sr}}_{0.6}\mathrm{Mn}{\mathrm{O}}_{3}$, a spontaneous magnetization is observed for $x<0.2$. It is demonstrated that, also in ${\mathrm{Mn}}^{+4}$-rich manganites, the magnetoresistive properties can be optimized by chemical pressure, the Sr for Ca substitution increasing the octahedra tilting in the $Pnma$ structure.

We report a comparative study of the magnetic properties of synthetic Cu3(OH)4(SO4)x(SeO4)1-x and the magnetic structures of the parent compounds. All compounds are isostructural and belong to the orthorhombic class of parent compounds. They consist of 3-legged ribbons of edge-sharing copper octahedra connected by micro3-OH and XO4 (X=S or Se). XO4 acts both as one-atom and three-atom bridges to connect seven Cu atoms (six Cu(2) and one Cu(1)) belonging to three neighboring ribbons. The two end members behave as low-dimensional AF with a long-range antiferromagnetic state below 5 (X=S) and 8 K (X=Se); the former shows evidence of a canting. Analyses of the neutron powder diffraction data for X=S were shown to display an ordered magnetic state (k=0 0 0) where the moments of Cu(2) within the two outer legs are collinear and parallel within each leg but antiparallel from each other; the orientation of the moments of Cu(2) is the c axis. In contrast, for X=Se k=approximately 1/7 0 0 and the magnetic structure is cycloidal and transforms progressively from being incommensurate (T>3 K) to commensurate (T<or=3 K). The moments of Cu(2) of each leg are oriented antiparallel as for X=S, but they rotate about the b axis while propagating along the a axis. In both cases the moments of Cu(1) of the inner leg remain random. The magnetic entropy of 15.2+/-1 J/kmol for the end members, estimated from integrating the heat capacity/temperature, is close to that expected (3R ln 2) for three Cu2+ (S=1/2).

Synthetic Cu3(OH)2(MoO4)2 consists of Cu3(OH)2 brucite ribbons of edge-sharing copper octahedra connected by MoO4 into a 3D network as in the mineral, lindgrenite, for all temperatures between 1.5 and 300 K. Each ribbon consists of a triangular connection between two different types of copper atom (Cu(1) and 2 Cu(2)) via mu3-OH. The MoO4 acts both as one- and three-atom bridges to connect six Cu atoms belonging to three adjacent ribbons. The magnetic properties are consistent with those of ferrimagnetic chains, and the resulting moment of each chain is parallel below the long-range magnetic ordering at 13 K. The Curie constant is 0.468(1) emu K mol-1 of Cu; the Weiss temperature is -14.2(2) K, and the saturation magnetization at 2 K in 50 kOe is 0.41 N muB mol-1 of Cu. Analyses of the neutron powder diffraction reveal an ordered magnetic state where the moment of Cu(1) is antiparallel to those of the two Cu(2); all of them point along the a axis without any sign of geometrical frustration. Any degeneracy that may be present because of the triangular topology of the Cu atoms (s = 1/2) appears to be lifted by the distortion from an ideal equilateral geometry of the triangle. The entropy, estimated from the heat capacity measurements, attains 50% of the total of 17.7 J K-1 mol-1, close to that expected for three Cu atoms (3R ln 2), up to the long range ordering temperature, and the remaining is associated with the low dimensionality of the material.

The crystal structures of the hydrides of austenitic and martensitic Ti0.64Zr0.36Ni alloy have been investigated by conjoint X-ray diffraction (XRD)–neutron diffraction (ND) analysis. Austenitic Ti0.64Zr0.36Ni alloy with cubic CsCl-type structure preserves its metal sublattice structure after deuteration. It forms a Ti0.64Zr0.36NiD1.5 deuteride with D-atoms occupying half of the octahedrally coordinated 3d sites. On the contrary, the monoclinic TiNi-type structure of martensitic Ti0.64Zr0.36Ni alloy is modified after deuterium absorption. At PD2=103Pa and T=298K, two deuterides coexist with orthorhombic CrB-type structure for the metal sublattice and compositions Ti0.64Zr0.36NiD (β-deuteride) and Ti0.64Zr0.36NiD2.6 (γ-deuteride). For the β-monodeuteride, deuterium atoms are tetrahedrally coordinated by (Ti,Zr) atoms. For the γ-deuteride, D-atoms fully occupy tetrahedrally coordinated (Ti,Zr)3Ni 8f sites and partially occupy pyramidal (Ti,Zr)3Ni2 4c sites. At higher pressures, deuterium solution occurs in the γ-phase with a partial occupancy of octahedrally coordinated (Ti,Zr)2Ni4 4a sites.

The crystal structure and stability of Ba4CaCu3O8+δ have been investigated by neutron powder diffraction, differential thermal analysis and thermogravimetry. It is found that the phase is not stable below 1065K in p(O2)=1bar and decomposes according to the eutectoid reaction Ba4CaCu3O8+δ+x O2⇒Ba2CuO3.4+CaO+2BaCuO2. However, the equilibrium with the outer gas is not reached for sintered ceramics so that Ba4CaCu3O8+δ can be obtained in a metastable state after normal cooling conditions. In this case, the crystal structure is cubic (Im-3m, a=8.1452(1)Å, δ=0.68, Z=2, Rwp=2.5%, RBragg=5.4%) as reported in the literature. In reduced oxygen partial pressure (p(O2)<10−6bar), Ba4CaCu3O8+δ is stable down to room temperature and has a tetragonal structure with a significant lower oxygen content (P4/mmm, a=8.1976(3)Å, c=8.0709(3)Å, δ=-0.81, Z=2, Rwp=2.8%, RBragg=5.1%). The difference between the two crystal structures is discussed in terms of oxygen content, copper formal valence and cation coordination. The influence of the oxygen pressure on the stability of Ba4CaCu3O8+δ is also discussed.

[Mn(3)(OH)(2)(SO(4))(2)(H(2)O)(2)] and its deuterated analogue were synthesized by a hydrothermal technique and characterized by differential thermal analysis, thermogravimetric analysis, and IR spectroscopy. Its nuclear structure, determined by single-crystal X-ray analysis and Rietveld analysis of neutron powder-diffraction data, consists of a 3D network of chains of edge-sharing Mn(1)O(6), running along the c axis, connected by the apices of Mn(2)O(6) and SO(4) units. It is isostructural to the nickel analogue. Determination of the magnetic structure and measurements of magnetization and heat capacity indicate the coexistence of both magnetic long-range ordering (LRO) and short-range ordering (SRO) below a Néel temperature of 26 K, while the SRO is retained at higher temperatures. The moments of the two independent Mn atoms lie in the bc plane, and that of Mn(1) rotates continuously by 54 degrees towards the c axis on decreasing the temperature from 25 to 1.4 K. While the SRO may be associated with frustration of the moments within a Mn(3) trimer, the LRO is achieved by antiparallel alignment of the four symmetry-related trimers within the magnetic unit cell. A spin-flop field, measured by dc and ac magnetization on a SQUID, is observed at 15 kOe.

The deuterides of three intermetallic compounds LaNi5+x with x=0, 0.2 and 0.4 have been prepared and analyzed by neutron powder diffraction at two different deuterium concentrations. On one hand, the crystallographic properties of the α and the β phases have been studied with the two phases in equilibrium on the pressure plateau characteristic for the phase transition. On the other hand, the β phase has been studied as a single phase in the solid solution domain. Crystal structures were refined using the Rietveld method. Crystal symmetry, lattice parameters and deuterium sites and occupancy parameters are reported for all the different phases. Anisotropic line profile analysis has been used to characterize the strains induced by deuterium absorption in the various regions of the Pressure–Composition–Isotherm curves. Results are compared for the different values of x and related to the cycle life properties for each compound.

We present the synthesis, characterization by DT-TGA and IR, single crystal X-ray nuclear structure at 300 K, nuclear and magnetic structure from neutron powder diffraction on a deuterated sample at 1.4 K, and magnetic properties as a function of temperature and magnetic field of Ni(3)(OH)(2)(SO(4))(2)(H(2)O)(2). The structure is formed of chains, parallel to the c-axis, of edge-sharing Ni(1)O(6) octahedra, connected by the corners of Ni(2)O(6) octahedra to form corrugated sheets along the bc-plane. The sheets are connected to one another by the sulfate groups to form the 3D network. The magnetic properties measured by ac and dc magnetization, isothermal magnetization at 2 K, and heat capacity are characterized by a transition from a paramagnet (C = 3.954 emu K/mol and theta = -31 K) to a canted antiferromagnet at T(N) = 29 K with an estimated canting angle of 0.2-0.3 degrees. Deduced from powder neutron diffraction data, the magnetic structure is modeled by alternate pairs of Ni(1) within a chain having their moments pointing along [010] and [010], respectively. The moments of Ni(2) atoms are oppositely oriented with respect to their adjacent pairs. The resulting structure is that of a compensated arrangement of moments within one layer, comprising one ferromagnetic and three antiferromagnetic superexchange pathways between the nickel atoms.

An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Cu3(OH)4SO4, obtained by hydrothermal synthesis from copper sulfate and soda in aqueous medium, is isostructural with the corresponding antlerite mineral, orthorhombic, space group Pnma (62), with a=8.289(1) b=6.079(1) and c=12.057(1)Å, V=607.5(2) Å3, Z=4. Its crystalline structure has been refined from X-ray single crystal and powder neutron diffraction data at room temperature. It consists of copper (II) triple chains, running in the b-axis direction and connected to each other by sulfate groups. The magnetic structure, solved from powder neutron diffraction data at 1.4K below the transition at 5K evidenced by susceptibility and specific measurements, reveals that, inside a triple chain, the magnetic moments of the copper ions (μB=0.88(5) at 1.4K) belonging to outer chains are oriented along the c-axis of the nuclear cell, with ferromagnetic order inside a chain and antiferromagnetic order between the two outer chains. No long-range magnetic order is obtained along the central chain with an idle spin behavior.

We report on an analysis of strain and crystallite size effects in mechanically alloyed PbTe. The evolution of the microstructure was monitored by Rietveld refinements of the neutron powder diffraction data collected at room temperature. For milling times shorter than 6h, the synthesis is not completed and the samples are clearly multi-phase with high concentrations of unreacted starting constituents. For longer milling times, the diffraction patterns are consistent with a single-phase PbTe. Within the range of reaction times studied, the crystallite size decreases with an exponential decay law and saturates to a value of 26nm. However, the strain parameter does not show such a monotonic behavior. Indeed, it first increases and reaches a maximum when the synthesis is achieved and then drops for longer milling time as a result of the thermal activated annealing induced by additional mechanical shocks.

The structure of ZrFe2 and ZrCo2 deuterides prepared under very high deuterium pressure has been studied by neutron diffraction (ND) at 10 K. The patterns of both compounds are refined with a mixture of intermetallic compound and deuteride. For ZrFe2Dx, the cell volume increases with 23% and the 2.7 D/f.u. are located randomly in A2B2 sites. The Fe moments order in a ferromagnetic structure and increase from 1.8 to 2.2 μB/Fe upon D absorption. The ZrCo2 deuteride shows a doubling of the cell parameter due to deuterium order of 2 D/f.u. in 7 over 12 A2B2 sites with a cell volume increase of 12%.

Cu3(OH)4SO4 and Cu4(OH)6SO4, synthetic equivalent of antlerite and brochantite minerals, have been obtained by hydrothermal synthesis from copper sulfate, soda and H2O or D2O. Their structures have been refined from single crystal X-ray and/or powder neutron diffraction data. They consists of edge-shared copper octahedron infinite chains connected to each other to define either triple chains in the case of antlerite or corrugated planes in the case of brochantite. Sulfate groups connect the former copper entities. From magnetic susceptibility measurements, both samples reveal a transition towards a 3D antiferromagnetic long range order at low temperature. In the paramagnetic domain, AF interactions are predominant for brochantite whereas ferromagnetic ones are evidenced for antlerite. The magnetic structures have been determined from powder neutron diffraction data and reveal the presence of ferromagnetic chains AF coupled. The magnetic results have been related to the Cu-O-Cu bridge angle values.

Intermetallic compounds that reversibly store hydrogen gas at room temperature and pressure are used in numerous devices including hydrogen gas storage units, fuel cells, hydrogen purification and heat-pump systems. LaNi5-xMx (M=Sn, Ge; 0≤x≤0.4), substitutional derivatives of LaNi5, are being used in sorption cryocoolers for applications in space. This study deals with structural characterizations of LaNi4.6Ge0.4 and of its hydride (deuteride) including the hydrogen insertion sites in the metallic matrix and their occupancies. Results are compared to properties of Sn-substituted phases.

Since few years, cerium filled and partially filled skutterudites are intensively studied because they show a wide variety of fundamental and applied properties. One of them consists in high values of thermal factors for rare earth atom in antimony skutterudites [1,2]. Slack suggests [3,4] a incoherent rattling of this ion in the oversized cage “Sb 12 ” surrounding the cerium which affects highly the phonon motion and thus lowers the lattice thermal conductivity (k l ). As a rule, the lattice thermal conductivity is decreased by a factor of 5 or greater by filling entirely the voids of the binary filled skutterudites with rare earth atoms [5]. Besides, k l decreases for partially filled compounds in respect with totally filled ones [6,7]. Mass fluctuation mechanism between cerium atom and vacancy is obviously involved as the origin of this last reduction. On that purpose, theoretical calculations [7] demonstrate that the reduction belonging to mass fluctuation mechanism is an order of magnitude lower than the measured decrease. As the mass fluctuation added to the “rattling” on the cerium site is not sufficient to explain such low values of thermal conductivity, another phonon scattering mechanism must exist. In order to find another mechanism we present the influence of the filling fraction of cerium on thermal factors and the temperature dependence of this factor for a partially filled compound.

The structural and magnetic properties of YMn2D1.15 have been investigated by temperature-dependent neutron diffraction. Magnetic and deuterium orders appear below Tc=217 K. To separate both effects and to study only magnetic ordering, hydrogen atom contribution was cancelled by preparing the compound YMn2(H0.64D0.36)1.15. A noncollinear magnetic structure with 3.1 μB/Mn is observed. Finally the low-temperature structure was fully solved taking into account both deuterium and magnetic contributions. Whereas the deuterium atoms are rand-omly distributed over all the 96g sites (Fd3m) above 217 K, only 12i sites in space group P43m are occupied at low temperature.