Search results for "FERROMAGNET"
showing 10 items of 995 documents
A polymeric two-dimensional mixed-metal network. Crystal structure and magnetic properties of {[P(Ph)4][MnCr(ox)3]}
1994
Abstract The mixed-metal ferromagnet {[P(Ph) 4 ][MnCr(ox) 3 ]} n , where Ph is phenyl and ox is oxalate, has been prepared and a two-dimensional network structure, extended by Mn(II)-ox-Cr(III) bridges, has been determined from single crystal X-ray data. Crystal data: space group R 3 c , a = b =18.783(3), c =57.283(24) A, α=β=90, γ=120°, Z =24 (C 30 H 20 O 12 PCrMn). The magnetic susceptibility data obey the Curie-Weiss law in the temperature range 260–20 K with a positive Weiss constant of 10.5 K. The temperature dependence of the molar magnetization exhibits a magnetic phase transition at T c =5.9 K. The structure is discussed in relation to the strategy for preparing molecular based ferr…
Antiferromagnetic Interactions in Copper(II) µ-Oxalato Dinuclear Complexes: The Role of the Counterion
2018
We report the preparation, crystal structure determination, magnetic properties and DFT calculations of five oxalato-bridged dicopper(II) complexes of formula [Cu-2(bpy)(2-)(H2O)(2)(C2O4)](CF3SO3)(2) (1), [Cu-2(bpy)(2)(C2O4)](PF6)(2) (2), [Cu-2(bpy)(2)(C2O4)](ClO4)(2) (3), [Cu-2(bpy)(2)Cl-2(C2O4)]center dot H2O (4) and [Cu-2(bpy)(2)(NO2)(2)(C2O4)] (5) (bpy = 2,2'-bipyridine and C2O42-= oxalate). Compounds 1, 2, 4 and 5 crystallize in the monoclinic system and 3 crystallizes in the triclinic system. The oxalate ligands in 1-5 adopt the bis-bidentate coordination mode and the two bpy molecules act as terminal ligands. The coordination of the counterions and the surroundings of the copper(II) …
The magnetic resonance of Gd3+ in Gd2Se3 near the phase transition and up to 300 K
1985
Temperature dependences of the width of the Gd2Sc3 ESR lines are investigated. The observed width is satisfactory explained by a dipole mechanism narrowed by exchange interaction. Changes of the Gd2Se3 ESR line at T = 6 K are due to antiferromagnetic ordering in the sample. Es wird die Temperaturabhangigkeit der ESR-Linienbreite von Gd2Se3 untersucht. Die beobachtete Breite wird durch einen Dipolmechanismus mit Verschmelzung durch Austauschwechselwirkung beschrieben. Anderungen der Gd2Se3-ESR-Linie bei T = 6 K werden infolge antiferromagnetischer Ordnung in der Probe hervorgerufen.
Electrically Driven Magnetic Domain Wall Rotation in Multiferroic Heterostructures to Manipulate Suspended On-Chip Magnetic Particles
2015
In this work, we experimentally demonstrate deterministic electrically driven, strain-mediated domain wall (DW) rotation in ferromagnetic Ni rings fabricated on piezoelectric [Pb(Mg1/3Nb2/3)O3]0.66-[PbTiO3]0.34 (PMN-PT) substrates. While simultaneously imaging the Ni rings with X-ray magnetic circular dichroism photoemission electron microscopy, an electric field is applied across the PMN-PT substrate that induces strain in the ring structures, driving DW rotation around the ring toward the dominant PMN-PT strain axis by the inverse magnetostriction effect. The DW rotation we observe is analytically predicted using a fully coupled micromagnetic/elastodynamic multiphysics simulation, which v…
Electric Field Control of Spin-Dependent Dissipative Electron Transfer Dynamics in Mixed-Valence Molecules
2015
We demonstrate that the borderline class II/III magnetic MV dimers, which can be referred to as single molecule multiferroics, provide a unique possibility to achieve electric field control of the electron transfer (ET) dynamics. As an example, we consider a MV dimer d2-d1 in which an extra electron is delocalized over two spin-cores (s0 = 1/2), and the ET is spin-dependent due to the double exchange mechanism. It is assumed that the “extra” electron is coupled to the only intramolecular vibration, and a weak coupling to the dissipative subsystem (thermal bath) is taken into account. The vibronic energy levels and the wave functions of the isolated dimer (quantum part of the system) are num…
D-Q axis theory of thermomagnetic Curie motor
2010
This paper presents a the d-q axis theory of a thermomagnetic Curie motor. From this theory a maximization procedure of the performances of Curie motor has been developed. The proposed approach has shown that the thermomagnetic Curie motor is equivalent from a magnetic point of view to a d.c. electric machine. Consequently, a design of a Curie motor has been proposed and the calculated performances show a significant improvement in comparison to the performances reported in literature.
Magnetic and structural approach for understanding the electrochemical behavior of LiNi0.33Co0.33Mn0.33O2 positive electrode material
2013
Abstract A systematic study has been performed to investigate the structural and magnetic changes in LiNi 0.33 Mn 0.33 Co 0.33 O 2 , a member of the LiNi y Mn y Co 1–2 y O 2 series, upon chemical lithium deintercalation. Structural characterization of the chemically delithiated Li x Ni 0.33 Mn 0.33 Co 0.33 O 2 samples indicates that the initial rhombohedral symmetry (α-NaFeO 2 type structure) is maintained in the whole 0.3 ≤ x ≤ 1.0 composition range. Less than 1% variation in the hexagonal unit cell volume was evidenced showing a good structural stability of this sample. SEM pictures of the delithiated phases confirm this stability. Indeed, the particle size average undergoes a small dec…
Site symmetry approach in the supercell model of carbon-doped ZnO bulk
2017
Abstract Carbon-doped zinc oxide is one of promising materials for technological applications due to its ferromagnetism observed at room temperature. When using the hybrid DFT-HF Hamiltonian based on the PBE0 exchange-correlation functional for large-scale calculations on defective ZnO:C single crystal, we have shown that application of supercell model for carbon impurity located at O site of wurtzite-structured ZnO bulk results in the dependence of calculated formation energy of the point defect (Eform) on the selected site symmetry of the substituted atom in the supercell. For a more symmetric C3v site usually used for simulation of defective ZnO structures, values of formation energy per…
Characterisation of electric alloys for electric drives
1996
Knowledge of the magnetic and loss charactenstics of electric alloys is necessary for the computation and design of electrical machines. Over a long period of time, and more recently, many devices have been proposed for this characterisation. They test ferromagnetic sheets under conditions of unidirectional magnetic flux density. Other methods are derived from some of these devices, but they use conditions of rotating flux density. In the paper the authors show with the use of numerical computation that, in all these testing systems, the distribution of the magnetic flux density through the thickness of the sheet is uniform and does not take into account the edge effect which exists in rota…
Synthesis, structural analysis, and magnetic properties of ethylmalonate-manganese(II) complexes
2011
12 páginas, 10 figuras, 6 tablas.-- et al.