Magnetic structure of Nd7Ni3 (original) (raw)

Neutron diffraction studies of rare earth compound Nd7Ni3 in an external magnetic field

Journal of Physics and Chemistry of Solids, 1999

Neutron diffraction experiments were carried out to determine the magnetic structure of Nd 7 Ni 3 in an external field. At 4.2 K and in external fields below 1.3 T the magnetic structure is conical with a basal plane helical component having a propagation vector Q (0, 0, 1/3) and a c-axis ferromagnetic component. Above 1.3 T the c-axis component disappears, while the basal plane component remains up to 2.7 T. Below 0.3 T, the magnetic structure changes from conical to helical at about 8 K. A rough (H, T) phase diagram is given and is generally consistent with the results of magnetization measurements. ᭧

Structural and magnetic properties of Nd3(Fe1−xCox)27.7Ti1.3 (0

Journal of Alloys and Compounds, 2001

Structural and magnetic properties of a novel series of intermetallic compounds, with nominal stoichiometry Nd (Fe Co) Ti 3 1 2x x 27.7 1.3 (0,x#0.4) are presented. The samples crystallise in the Nd (Fe,Ti)-type structure with monoclinic symmetry (space group A2 /m). The 3 2 9 unit cell volume is decreasing as the Co content increases; the cell parameters show anisotropic decrease with the Co content. The Curie temperature increases monotonically with x from 437 to 878 K and the room temperature saturation magnetisation increases from 143.3 2 for x50 to 172.5 Am / kg for x50.3 and remains practically the same for x50.4. For x50 and 0.1 a tilted magnetic structure is observed. For x$0.2 the compounds present an easy-magnetisation direction along the [4 0 22] direction. Ac susceptibility curves in the whole range of the Co content (x50-0.4) reveal a broad transition at about 160 K, whereas for x50-0.2 a sharp one with the corresponding transition temperature decreasing with increasing Co content. The observed changes of the critical temperatures observed in the ac susceptibility curves and the obtained anisotropy field values are related to the change of the magnetic anisotropy at x50.2. The average hyperfine field values depend on the Co content in a way similar to the dependence of the saturation magnetisation.

Neutron Diffraction and TEM Studies of the Crystal Structure and Defects of Nd4Ni3O8

Journal of Solid State Chemistry, 1998

Powder neutron diffraction and electron microscopy studies confirmed the crystal structure of Nd4Ni3O8(space groupI4/mmm;a=b=3.9168(2) Å,c=25.322(2) Å,Z=4; reliability factorsRp=0.125,Rwp=0.108,χ2=2.81,RBragg=0.043,RF=0.037) previously determined by powder X-ray diffraction [Ph. Lacorre,J. Solid State Chem.97, 495 (1992)]. It consists in the intergrowth between triple layers of nickel in square planar coordination with Nd in cubic coordination (infinite layer type) and fluorite type layers. Nd4Ni3O8is thus the

A magnetic and neutron diffraction study of the interstitial Nd(Fe,Si)C compound

Journal of Magnetism and Magnetic Materials, 2005

A sample of nominal composition NdFe 9 Si 2 C 0:5 was prepared by arc-melting. The crystallographic structure and the magnetic properties of the obtained compound were investigated by means of X-ray and neutron powder diffraction, and magnetic measurements. The compound crystallises within a filled variant of the tetragonal BaCd 11 -type structure, with Nd in 4a position and Fe in the 4b, 32i and 8d sites, the Si atoms being located on the remaining part of 8d sites and the carbon atoms occupying 8c octahedra formed by four Fe and two Nd atoms. From the neutron diffraction study, the composition is found to be close to NdFe 10:6 Si 0:4 C 0:6 : Thus the quantity of Si entering this material is less than expected: we infer that a stoechiometric NdFe 9 Si 2 C 0:5 compound cannot be obtained. The Curie temperature is equal to 317(2) K, and the saturation magnetisation at 4 K is 16.65 m B =f :u: At 2 K, a significant difference is observed in the Fe moment amplitudes between the 32i site (m Fe $ 1:5 m B ) on the one hand, and the 4b (m Fe $ 2:9 m B ) and 8d sites (m Fe $ 2:5 m B ) on the other hand. r

Neutron diffraction studies on an exotic magnetic system, Nd 7 Rh 3

Journal of Physics: Conference Series, 2012

Binary intermetallic compound Nd 7 Rh 3 crystallizes in a Th 7 Fe 3 type hexagonal structure in space group P6 3 mc and has been reported to show two antiferromagnetic (AFM) phase transitions at 32 K and 10 K from magnetic susceptibility, and a field induced first-order magnetic transition at a field strength of 1 Tesla at 2 K from magnetization measurements. These magnetic properties are different from the isostructural counterparts like Tb 7 Rh 3 , Ho 7 Rh 3 , and Nd 7 Ni 3. In order to understand the differences in the magnetic behaviour between Nd 7 Rh 3 and other isostructural compounds, we have carried out neutron diffraction (ND) studies on polycrystalline Nd 7 Rh 3 at various temperatures between 2 and 45 K. ND patterns were also recorded at T = 2K in the presence of applied magnetic fields from 0 to 1.5 Tesla. ND spectra on Nd 7 Ni 3 and Ho 7 Rh 3 , for example, at 2 K in zero magnetic field exhibit a strong AFM peak at a Q (= 4 Sin /) value of 0.32 and 0.38 Å-1 , respectively. However, ND spectra on Nd 7 Rh 3 , carried out at Focusing Crystal Diffractometer (FCD-Dhruva-Mumbai), diffractometers E6 and E9 (HZB-Berlin) using wavelengths = 1.48Å, 2.45Å and 2.8Å respectively, at T = 2K in zero field do not exhibit any AFM peaks in the entire Q-range studied. Instead, long-range ferromagnetic order is established as evidenced by the intensity enhancement of the nuclear Bragg peaks. The lack of extra peaks in the ND patterns would imply that the magnetic order seen in magnetization could be of a k = 0 type which changes from one type to another on the application of magnetic field. The results of nuclear and magnetic structure refinement are discussed to explain the magnetic behaviour of Nd 7 Rh 3 at low temperatures.

Magnetic structure of NdMn$_{0.8}$Fe$_{0.2}$O$_{3+\delta}$; neutron powder diffraction experiment

Magnetic structure of NdMn$_{0.8}$Fe$_{0.2}$O$_{3+\delta}$ was determined from neutron powder diffraction measurements. Our study revealed that the Mn sublattice orders below TNT_NTN = 58.6(5) K with k-vector k = (0 0 0). The ordered magnetic moments possess antiferromagnetic component which is oriented along the a-axis and ferromagnetic component oriented along the b-axis. The Nd sublattice orders ferromagnetically below T1T_1T1 = 12.4(5) K with magnetic moments oriented parallel to the b-axis. The extrapolated ordered magnetic moment ($\mu_0$) to temperature T = 0 K was found to be considerably smaller [$\mu_{0Nd}$ = 1.58(3) muB\mu_BmuB; mu0Mn\mu_{0Mn}mu0Mn = 3.31(2) muB\mu_BmuB] than the expected ordered magnetic moments for Nd$^{3+}$ and Mn$^{3+}$ ions.

Magnetic structure in the segregated phases Nd0.93MnO2.96

Journal of Alloys and Compounds, 2009

We report complete information on a structural model (involving two perovskite phases with a slight different chemical composition and magnetic ordering temperatures) that is introduced in order to interpret powder neutron diffraction (PND) and magnetic measurement on Nd 0.93 MnO 2.96 manganites. The magnetic structure derived from PND data shows that the Mn magnetic sub-lattice for both phases become ordered below T N = 80 K corresponding to a canted ferromagnet with a spin arrangement (Cx, Fy, 0). The Nd magnetic sub-lattice for both phases becomes polarized below T = 19 K having a unique ferromagnetic component parallel to the ferromagnetic component Fy of the Mn sub-lattice.

Structural and magnetic investigation of the Nd3Co13−xNixB2 compounds

Journal of Magnetism and Magnetic Materials, 2005

The Nd 3 Co 13Àx Ni x B 2 series of compounds, with the Nd 3 Ni 13 B 2 -type structure and x ¼ 0; 2, 5, 7 and 13, were synthesized by induction melting and short annealing time, in contrast to the prolonged period of annealing, which was reported previously. The full structural determination is given and the magnetic properties are investigated by means of AC susceptibility and magnetization measurements. The composition dependences of the spin reorientation temperature, Curie temperature and cobalt moment are derived. The magnetic anisotropy and exchange interactions are discussed. r