Anomalous magnetic properties in LaFe11.5Al1.5

2020 ◽  
Vol 22 (6) ◽  
pp. 3425-3433
Author(s):  
Sanjay Sharma ◽  
Faizan Ahmad ◽  
Ankit Singh ◽  
Akhilesh Kumar Patel ◽  
Pramod Kumar

We report the magnetic relaxation, DC magnetization, heat capacity, and X-ray powder diffraction studies of a melt-spun LaFe11.5Al1.5 compound executed across a temperature range of 5 to 300 K.

2009 ◽  
Vol 64 (10) ◽  
pp. 1107-1114 ◽  
Author(s):  
Thomas Harmening ◽  
Matthias Eul ◽  
Rainer Pöttgen

New nickel-deficient stannides Eu2Ni2−xSn5 were synthesized by induction melting of the elements in sealed tantalum tubes. The solid solution was studied by X-ray powder diffraction and two crystal structures were refined on the basis of X-ray diffractometer data: Cmcm, a = 466.03(4), b = 3843.1(8), c = 462.92(9) pm, wR2 = 0.0469, 692 F2 values, 39 variables for Eu2Ni1.49(1)Sn5 and a = 466.11(9), b = 3820.1(8), c = 462.51(9) pm, wR2 = 0.0358, 695 F2 values, 39 variables for Eu2Ni1.35(1)Sn5. This new structure type can be considered as an intergrowth structure of CaBe2Ge2- and CrB-related slabs. The striking structural motifs are nickel-centered square pyramids which are condensed via common corners and edges. The layers of condensed NiSn5 units are separated by the europium atoms. The Ni1 sites within the CaBe2Ge2 slabs show significant defects which leads to split positions for one tin site. Eu2Ni1.50Sn5 shows Curie-Weiss behavior and an experimental magnetic moment of 7.74(1) μB / Eu atom, indicating stable divalent europium, as is also evident from 151Eu Mössbauer spectra. Antiferromagnetic ordering is detected at 3.5 K.


2005 ◽  
Vol 473-474 ◽  
pp. 117-122 ◽  
Author(s):  
A.C. Kis ◽  
Th. Leventouri ◽  
J.R. Thompson

Structure and magnetic properties of ferrimagnetic bioceramics in the system {0.45(CaO, P2O5) ySiO2 xFe2O3 0.03Na2O}, x=0.05, 0.10, 0.15, 0.20, were studied by x-ray powder diffraction and magnetic measurements. Magnetite and calcium phosphate, crystallizing in the hexagonal and monoclinic crystal systems, are the major phases in the compounds. Phase development, crystal structure, and magnetic properties of the composites are determined by the specific starting composition of oxides and the heat-treatment temperature.


Clay Minerals ◽  
1988 ◽  
Vol 23 (4) ◽  
pp. 367-377 ◽  
Author(s):  
D. H. Doff ◽  
N. H. J. Gangas ◽  
J. E. M. Allan ◽  
J. M. D. Coey

AbstractPillared smectites in which the pillars consist of iron oxide are expected to have interesting and unusual magnetic properties. Several possible routes by which such materials might be made have been investigated, namely intercalation of hydroxy-Fe(III) polycations, mixed hydroxy-Fe(III)/Al polycations, phenanthroline-Fe(II) cations, and trinuclear Fe(III) acetato cations into Na-montmorillonite. Only the last of these yielded a pillared clay (PILC) on calcination. The products have been characterized using X-ray powder diffraction and 57Fe Mössbauer spectroscopy. The precursor Fe-PILC has a d-spacing of 21 Å and expands to 23 Å on solvation with glycol. The calcined Fe-PILC has a d-spacing of 19 Å (gallery height 9·4 Å) and does not expand with glycol, confirming cross-linking of the layers. From Mössbauer spectra at 4·2 K it is estimated that there are of the order of some hundred Fe atoms per pillar.


2020 ◽  
Vol 75 (1-2) ◽  
pp. 191-199
Author(s):  
Aleksandr M. Golubev ◽  
Eva Brücher ◽  
Armin Schulz ◽  
Reinhard K. Kremer ◽  
Robert Glaum

AbstractPolycrystalline samples of La- and Lu-agardite with the composition RECu6(OH)6(AsO4)3 · n H2O (RE = La, Lu; n≈3) have been prepared and the structure of the products was determined by X-ray powder diffraction studies. The characterization has been complemented by Raman and UV/Vis spectroscopic, magnetic and TGA investigations. DFT calculations support the conclusions drawn from the experiments. The arsenates RECu6(OH)6(AsO4)3 · n H2O (RE = La, Lu; n≈3) are isostructural with the mineral mixite and crystallize with a hexagonal structure which contains ribbons of edge-sharing [CuO5] square-pyramids extending along the hexagonal axis. They are interconnected via (AsO4)3− groups to form hexagonal tubes of about 10 Å inner diameter. Such zeolite-like tubes host water molecules, which can be reversibly removed at moderate temperatures (T≈100°C). Like in mixite and YCu6(OH)6(AsO4)3 · 3 H2O, the Cu2+ cations in RECu6(OH)6(AsO4)3 · n H2O (RE = La, Lu; n≈3) exhibit low-dimensional antiferromagnetic properties, which are subject to changes in the Cu–O–Cu bond lengths and angles due to the lanthanide contraction.


2015 ◽  
Vol 230 ◽  
pp. 297-302 ◽  
Author(s):  
Oksana V. Livitska ◽  
Nataliya Yu. Strutynska ◽  
Igor V. Zatovsky ◽  
Nikolay S. Slobodyanik

The interaction in the systemsMII2P4O12-MICl (MINO3) (MI– Li, Na, K;MII– Mg, Co, Ni, Zn) was investigated in temperature range 1073-673 K. The conditions of formation phosphates: Li3PO4,MIMIIPO4(MI– Na, K), Na4MII3(PO4)2P2O7, Na9Co3(PO4)5have been established. Obtained crystalline phases have been investigated using X-ray powder diffraction, Diffuse reflectance, Raman and FTIR spectroscopy and scanning electron microscopy methods.


2012 ◽  
Vol 05 ◽  
pp. 841-846
Author(s):  
AMIR KEYVANARA ◽  
REZA GHOLAMIPOUR ◽  
SHAMSEDIN MIRDAMADI ◽  
FARZAD SHAHRI ◽  
HOSSEIN SEPEHRI AMIN

Melt spun ribbons of Co 64 Fe 4 Ni 2 B 19 Si 8 Cr 3 alloy have been prepared and the nanocrystallization process was carried out by the heat treatment of the as spun ribbons above the crystallization temperature. Structural studies of the samples have been performed by transmission electron microscopy and X-ray diffraction. Magnetic properties of the samples and magnetoimpedance measurements were investigated and it was revealed that magnetic properties and magnetoimpedance of the samples deteriorate by the formation of nanocrystalline phases.


1987 ◽  
Vol 01 (03n04) ◽  
pp. 989-992 ◽  
Author(s):  
M.T. Causa ◽  
S.M. Dutrús ◽  
C. Fainstein ◽  
G. Nieva ◽  
H.R. Salva ◽  
...  

We report here normal and superconducting properties of ABa 2 Cu 3 O 7−δ (with A=Y, Gd, Dy, and Er) and of Fe doped YBa2Cu3O7−δ . Results from X-ray powder diffraction, electrical resistivity, magnetic susceptibility, ESR, and specific heat measurements are presented, leading to a characterization of the magnetic properties of these materials. The effect of structural modifications of the lattice on the superconducting properties and the relative insensitivity of Tc to the presence of magnetic moments is discussed.


1998 ◽  
Vol 12 (28) ◽  
pp. 1175-1183 ◽  
Author(s):  
I. Gr. Deac ◽  
A. V. Pop ◽  
V. Pop ◽  
R. Tetean ◽  
D. Kovacs ◽  
...  

The electrical and magnetic properties of ( Y 1-x-y Zr x Ca y) Ba 2 Cu 3 O 7-δ ceramics are investigated by using resistivity, ac and dc susceptibility measurements. X-ray powder diffraction has been used to find the lattice parameters of the samples. The samples are orthorhombic, except the sample with x=0.15 and y=0.2 which is tetragonal. All the samples are superconducting. There is no significant change in Tc for the Zr-doped ( Y 1-x Zr x) Ba 2 Cu 3 O 7-δ samples, while for the ( Y 0.85-y Zr 0.15 Ca y) Ba 2 Cu 3 O 7-δ compounds the Tc decrease with the dopant content and they show temperature dependent dc magnetic susceptibility, in the normal state.


1997 ◽  
Vol 233 (2-3) ◽  
pp. 95-101 ◽  
Author(s):  
J. Combet ◽  
M. Bée ◽  
D. Djurado ◽  
G. D'Assenza ◽  
G. Commandeur

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