Macroscopic and microscopic study of a CePdIn compound

The magnetization and electrical resistivity measurements on a CePdIn single crystal as well as its preparation and structural characterization are presented. The negative paramagnetic Curie temperatures indicate antiferromagnetic ground state, the anisotropy of the paramagnetic Curie temperature amounts 22.7 K. No ferromagnetic correlations were indicated. Powder neutron diffraction experiment performed at temperatures down to 0.4 K did not lead to observation of any magnetic peak in diffraction patterns. We estimate the magnetic moment on Ce atoms to be significantly lower than 0.5-B. The temperature development of lattice parameters documents the standard thermal expansion of the unit cell; no signs of structural phase transition were observed

Enabling of AUTOSAR system design using Eclipse-based tooling

International audienceAUTOSAR is a development partnership for standardisation of software architectures for the development of complex E/E systems. The software configuration process specified by AUTOSAR involves the handling of large amounts of data describing the E/E system. An efficient application of the process requires good and continuous toolsupport.In this paper we propose an approach for AUTOSAR tooling, which is based on the technology and, more important, on the idea of Eclipse. Eclipse is one of the most successful open source projects of the last years with a strong influence on the industry. It provides an open development platform that can easily be extended. On top of Eclipse, the approach provides an open tool basis, which can be extended by special, free or commercial plug-ins.Our AUTOSAR tooling approach is oriented towards the ideas behind Eclipse and focuses on reusing the success factors for a tool approach within the AUTOSAR community

Neutron diffraction studies of NdNi_{5}Sn compound

The neutron powder diffraction measurements of the NdNi5Sn compound have been performed. The obtained results indicate that this compound crystallizes in a hexagonal CeNi_{5}Sn-type crystal structure described by the space group P63/mmc. The parameters of the crystal structure at 1.55 and 14.8 K are determined. In contradiction to the magnetic data the long-range magnetic ordering was not detected up to 1.55 K

Competing Jahn Teller distortions and ferrimagnetic ordering in the geometrically frustrated system Ni1 xCuxCr2O4

Competing Jahn Teller distortions combined with geometrical frustration give rise to a rich phase diagram as a function of x Cu and temperature in the spinel system Ni1 xCuxCr2O4. The Jahn Teller distortion of the end members acts in opposite ways, with an elongation of the NiO4 tetrahedra resulting in a structural transition at TS1 317K in NiCr2O4, but a flattening in the CuO4 tetrahedra at TS1 846K in CuCr2O4. In both cases the symmetry is lowered from cubic Fd 3m to tetragonal I41 amd on cooling. In order to follow the influence of Jahn Teller active Ni2 and Cu2 ions on the structural and magnetic properties of chromium spinels, we have investigated a series of samples of Ni1 xCuxCr2O4 by x ray and neutron powder diffraction. In the critical range 0.10 lt; x Cu lt; 0.20, strong orthorhombic distortions were observed, where competing Jahn Teller activities between the Cu2 and Ni2 ions result in distortions along both the a and c axes. For Ni0.85Cu0.15Cr2O4, the orthorhombic structure Fddd is stabilized up to TS2 368 2 K, close to the first structural phase transition at TS1 374 2 K. A ferrimagnetic spin alignment of the Ni Cu and chromium atoms sets in at much lower temperature TC 95K in this compound. The end members NiCr2O4 and CuCr2O4 undergo this ferrimagnetic transition at TC 74 and 135 K, respectively. These transitions are accompanied by the structural change to the orthorhombic symmetry which relieves the frustration. NiCr2O4 and Ni0.85Cu0.15Cr2O4 undergo a second magnetic transition at TM2 24 and 67K due to a superimposed antiferromagnetic ordering of the Cr moments resulting in a noncollinear magnetic structure. In the system Ni1 xCuxCr2O4, the magnetic transitions TC and TM2 merge with increasing copper content up to x Cu similar to 0.5. For the Ni rich chromites, geometrical frustration causes a strong reduction of the chromium moments, where magnetic long range order coexists with a disordered spin liquid like or a reentrant spin glass like state. This paper provides insight into the interplay between the Jahn Teller effect, geometrical frustration, and long range magnetic order in these complex system

Lattice Instability and Competing Spin Structures in the Double Perovskite Insulator Sr2FeOsO6

The semiconductor Sr2FeOsO6, depending on temperature, adopts two types of spin structures that differ in the spin sequence of ferrimagnetic iron - osmium layers along the tetragonal c-axis. Neutron powder diffraction experiments, 57Fe M\"ossbauer spectra, and density-functional theory calculations suggest that this behavior arises because a lattice instability resulting in alternating iron-osmium distances fine-tunes the balance of competing exchange interactions. Thus, Sr2FeOsO6 is an example for a double perovskite, in which the electronic phases are controlled by the interplay of spin, orbital, and lattice degrees of freedom.Comment: 8 Pages, 3 Figure

Canted ferrimagnetism and giant coercivity in the nonstoichiometric double perovskite La2Ni1.19Os0.81O6

The nonstoichiometric double perovskite oxide La2Ni1.19Os0.81O6 was synthesized by solid state reaction and its crystal and magnetic structures were investigated by powder x ray and neutron diffraction. La2Ni1.19Os0.81O6 crystallizes in the monoclinic double perovskite structure general formula A2B B O6 with space group P21 n, where the B site is fully occupied by Ni and the B site by 19 Ni and 81 Os atoms. Using x ray absorption spectroscopy an Os4.5 oxidation state was established, suggesting the presence of about 50 paramagnetic Os5 5d 3 , S 3 2 and 50 nonmagnetic Os4 5d 4 , J eff 0 ions at the B sites. Magnetization and neutron diffraction measurements on La2Ni1.19Os0.81O6 provide evidence for a ferrimagnetic transition at 125 K. The analysis of the neutron data suggests a canted ferrimagnetic spin structure with collinear Ni2 spin chains extending along the c axis but a noncollinear spin alignment within the ab plane. The magnetization curve of La2Ni1.19Os0.81O6 features a hysteresis with a very high coercive field, HC 41 kOe, at T 5 K, which is explained in terms of large magnetocrystalline anisotropy due to the presence of Os ions together with atomic disorder. Our results are encouraging to search for rare earth free hard magnets in the class of double perovskite oxide

Crystal and magnetic structure o antiferromagnetic Mn2PtPd

We have investigated the crystal and magnetic structure of Mn2PtPd alloy using powder x ray and neutron diffraction experiments. This compound is believed to belong to the Heusler family having crystal symmetry I4 mmm TiAl3 type . However, in this work we found that the Pd and Pt atoms are disordered and thus Mn2PtPd crystallizes in the L10 structure having P4 mmm symmetry CuAu I type like MnPt and MnPd binary alloys. The lattice constants are a 2.86 and c 3.62 at room temperature. Mn2PtPd has a collinear antiferromagnetic spin structure below the N el temperature TN 866 K, where Mn moments of 4 amp; 956;B lie in the ab plane. We observed a strong change in the lattice parameters near TN. The sample exhibits metallic behaviour, where electrical resistivity and carrier concentration are of the order of 10 amp; 8722;5 amp; 937; cm and 1021 cm amp; 8722;3, respectivel

High Magnetic Field Behaviour of the Triangular Lattice Antiferromagnet, CuFeO_2

The high magnetic field behaviour of the triangular lattice antiferromagnet CuFeO_2 is studied using single crystal neutron diffraction measurements in a field of up to 14.5 T and also by magnetisation measurements in a field of up to 12 T. At low temperature, two well-defined first order magnetic phase transitions are found in this range of applied magnetic field (H // c): at H_c1=7.6(3)/7.1(3) T and H_c2=13.2(1)/12.7(1) T when ramping the field up/down. In a field above H_c2 the magnetic Bragg peaks show unusual history dependence. In zero field T_N1=14.2(1) K separates a high temperature paramagnetic and an intermediate incommensurate structure, while T_N2=11.1(3) K divides an incommensurate phase from the low-temperature 4-sublattice ground state. The ordering temperature T_N1 is found to be almost field independent, while T_N2 decreases noticeably in applied field. The magnetic phase diagram is discussed in terms of the interactions between an applied magnetic field and the highly frustrated magnetic structure of CuFeO_2Comment: 7 pages, 8 figures in ReVTeX. To appear in PR

Neutron diffraction study of spin and charge ordering in SrFeO(3-delta)

We report a comprehensive neutron diffraction study of the crystal structure and magnetic order in a series of single-crystal and powder samples of SrFeO$_{3-\delta}$ in the vacancy range $0 \leq \delta \leq 0.23$. The data provide detailed insights into the interplay between the oxygen vacancy order and the magnetic structure of this system. In particular, a crystallographic analysis of data on Sr8Fe8O23 revealed a structural transition between the high-temperature tetragonal and a low-temperature monoclinic phase with a critical temperature T = 75 K, which originates from charge ordering on the Fe sublattice and is associated with a metal-insulator transition. Our experiments also revealed a total of seven different magnetic structures of SrFeO$_{3-\delta}$ in this range of $\delta$, only two of which (namely an incommensurate helix state in SrFeO3 and a commensurate, collinear antiferromagnetic state in Sr4Fe4O11) had been identified previously. We present a detailed refinement of some of the magnetic ordering patterns and discuss the relationship between the magneto-transport properties of SrFeO$_{3-\delta}$ samples and their phase composition and magnetic microstructure.Comment: 37 page