Search results for "Magnetism"
showing 10 items of 1934 documents
New charge transfer salts of two organic π-donors of the tetrathiafulvalene type with the paramagnetic [Cr(NCS)6]3- anion
2003
cited By 9; International audience; The electrochemical combination of the paramagnetic anion [Cr(NCS)6]3- with the organic π-donors bis(ethylenedithio)tetrathiafulvalene (ET) and 4,5-bis(2-hydroxyethylthio) -4′,5′-ethylenedithiotetrathiafulvalene (DHET-EDTTTF) leads to two new radical cation salts, namely (ET)4 [Cr(NCS 6]·PhCN 1 and (DHET-EDTTTF)2 (NEt4)[Cr(NCS)6] 2. Both have been characterized by X-ray crystallography, magnetic and resistivity measurements. The structure of 1 consists of alternating inorganic layers generated by the anions and organic layers in which the PhCN molecules are inserted; the organic sub-lattice is built up from four different ET units, three of them with a ch…
Theoretical and computational studies of magnetic anisotropy and exchange coupling in molecular systems
2018
The field of molecular magnetism studies the magnetic properties of molecular systems as opposed to conventional metal-based magnets. The high chemical modifiability of the constituting molecules makes such materials highly versatile, and the small size of the building blocks leads to the rise of various quantum mechanical phenomena, such as tunneling and entanglement. These phenomena can then be further utilized in the construction of nanoscale quantum devices. This dissertation describes computational and theoretical studies in the field of molecular magnetism using state-of-the-art quantum chemical methods based on ab initio multireference approaches and broken symmetry density functional t…
On a numerical solution of the Maxwell equations by discrete exterior calculus
2014
Asymmetric hysteresis for probing Dzyalohsinskii-Moriya interaction
2016
The interfacial Dzyaloshinskii-Moriya interaction (DMI) is intimately related to the prospect of superior domain-wall dynamics and the formation of magnetic skyrmions. Although some experimental efforts have been recently proposed to quantify these interactions and the underlying physics, it is still far from trivial to address the interfacial DMI. Inspired by the reported tilt of the magnetization of the side edge of a thin film structure, we here present a quasi-static, straightforward measurement tool. By using laterally asymmetric triangular-shaped microstructures, it is demonstrated that interfacial DMI combined with an in-plane magnetic field yields a unique and significant shift in m…
BEM analysis of a piezoelectric structural health monitoring system for delamination detection
2013
In the present work a piezoelectric based structural health monitoring (SHM) system is analyzed with the aim of assessing the ability of the piezoelectric patch to detect both edge and embedded delaminations proper of flange-skin composite laminated structures. he boundary element model is developed for piezoelectric solids and is implemented by taking advantage of the multidomain technique to model laminated and cracked configurations. A non-linear spring model interface is then implemented in conjunction with an iterative procedure allowing for the simulation of the finite stiffness of the bonding layers as well as of the non-penetration condition of the delamination surfaces. he dynamic …
Diseño de matrices ordenadas de imanes moleculares basados en porfirinas
2017
Dentro de la disciplina conocida como Magnetismo Molecular, y a raíz del descubrimiento del compuesto conocido como Mn12 en 1993, ha surgido un gran interés por las moléculas que presentan una lenta relajación de la magnetización por debajo de una temperatura de bloqueo. A estas moléculas se les conoce como Imanes Unimoleculares (Single Molecule Magnets, SMMs). En la última década, la utilización de compuestos con un único centro metálico paramagnético (Single Ion Magnets, SIMs) se ha postulado como una de las nuevas estrategias utilizadas para la obtención de compuestos que presentan lenta relajación de la magnetización con barreras efectivas más elevadas. Además, desde un punto de vista e…
Magnetostructural characterization of compounds based on the highly anisotropic Mn(III) and Re(IV) metal ions
2019
El trabajo desarrollado en el marco de esta Tesis confeccionada como compendio de artículos se encuentra comprendido en el campo del Magnetismo Molecular y la Química de Coordinación. La investigación desarrollada se ha centrado en la caracterización estructural y estudio de propiedades magnéticas de sistemas basados en los iones metálicos Mn(III) y Re(IV). El primero es un ion 3d mientras que el último es un ion metálico 5d. Estos iones metálicos han sido seleccionados a cuenta de que, dados los altos valores de anisotropía y espín que presentan, pueden brindar resultados destacables desde el punto de vista del Magnetismo Molecular. Centrándonos en los complejos basados en Mn (III), se ha …
Generalized wave propagation problems and discrete exterior calculus
2018
We introduce a general class of second-order boundary value problems unifying application areas such as acoustics, electromagnetism, elastodynamics, quantum mechanics, and so on, into a single framework. This also enables us to solve wave propagation problems very efficiently with a single software system. The solution method precisely follows the conservation laws in finite-dimensional systems, whereas the constitutive relations are imposed approximately. We employ discrete exterior calculus for the spatial discretization, use natural crystal structures for three-dimensional meshing, and derive a “discrete Hodge” adapted to harmonic wave. The numerical experiments indicate that the cumulat…
Crystal field and magnetism with Wannier functions: Rare-earth doped aluminum garnets
2015
Using the recently developed method we calculate the crystal field parameters in yttrium and lutetium aluminum garnets doped with seven trivalent Kramers rare-earth ions. We then insert calculated parameters into the atomic-like Hamiltonian taking into account the electron-electron, spin-orbit and Zeeman interactions and determine the multiplet splitting by the crystal field as well as magnetic $\hat{g}$ tensors. We compare calculated results with available experimental data.
Demo 100. Atracción electrostática con vidrio y plástico
2013
Objetivo: Mostrar la atracción o repulsión entre cargas eléctricas.