Search results for "Ferro"
showing 10 items of 2451 documents
The Azimuthal Dependence of Exchange Bias Effect and its Analysis by Spin Glass Model in Ni0.8Fe0.2/CoxNi1−xO Bilayers
2021
Exchange bias (EB) effect has been vigorously researched for many years due to its possible applications in information storage and spintronics, especially in spin valves for magnetic recording devices. Even though many models have been expounded to this day, they do not prove convincingly the origins of EB effect. We attempt to establish the azimuthal dependence of EB effect with respect to varying the composition of the antiferromagnet CoxNi $_{\mathrm {1-x}}\text{O}$ and temperature. In this report, we deposited the bilayer thin films of Ni0.8Fe0.2/Co x Ni1− x O with $x$ varying from 0.4 to 0.8 by magnetron sputtering and studied the variation of exchange bias field and coercivity. The E…
Design of single cyanide-bridged tetranuclear bimetallic rectangles exhibiting ferromagnetic coupling
2005
Abstract The cyanide-bridged tetranuclear bimetallic rectangles ( XPh 4 ) 4 [ Fe 2 III Cu 2 II ( μ - CN ) 4 ( CN ) 8 ( L ) 2 ] · n H 2 O [X = P (1) and As (2); L = bpcam (1) and bpca (2); n = 4 (1) and 0 (2)] have been prepared and their crystal structures were characterized by single crystal X-ray diffraction; 1 exhibits intramolecular ferromagnetic interactions (J1 = +3.7 cm−1 and J2 = +7.0 cm−1, H = - J 1 [ S Fe ( 1 ) · S Cu ( 1 ) + S Fe ( 1 a ) · S Cu ( 1 a ) ] − J 2 [ S Fe ( 1 ) · S Cu ( 1 a ) + S Fe ( 1 a ) · S Cu ( 1 ) ] + D [ S Fe ( 1 ) z 2 + S Fe ( 1 a ) z 2 ] ) leading to a low-lying S = 2 spin state.
Giant Edelstein effect in Topological-Insulator--Graphene heterostructures
2017
The control of a ferromagnet's magnetization via only electric currents requires the efficient generation of current-driven spin-torques. In magnetic structures based on topological insulators (TIs) current-induced spin-orbit torques can be generated. Here we show that the addition of graphene, or bilayer graphene, to a TI-based magnetic structure greatly enhances the current-induced spin density accumulation and significantly reduces the amount of power dissipated. We find that this enhancement can be as high as a factor of 100, giving rise to a giant Edelstein effect. Such a large enhancement is due to the high mobility of graphene (bilayer graphene) and to the fact that the graphene (bil…
Hybrid Interfaces in Molecular Spintronics
2018
Molecular/inorganic multilayer heterostructures are gaining attention in molecular electronics and more recently in new generation spintronic devices. The intrinsic properties of molecular materials as low cost, tuneability, or long spin lifetimes were the original reasons behind their implementation. However, the non-innocent role played by these hybrid interfaces is a determinant factor in the device performance. In this account we will give an overview about different types of hybrid molecular system/ferromagnet interfaces, which can be of direct application in molecular spintronics. This includes the insertion of a 2D material in between the molecular system and the ferromagnet. As pers…
Spintronic properties of Li1.5Mn0.5Z (Z=As, Sb) compounds in the Cu2Sb structure
2015
Abstract We have investigated the spintronic properties of two formula units of Li1.5Mn0.5Z (Z=As, Sb), in the Cu2Sb tetragonal crystal structure based on first-principles density-functional theory calculations, at, and near, their equilibrium (minimum total energy) lattice constants. Two groups of configurations, A and B, are formed for each type of alloy by interchanging Mn with each Li located at four different positions with respect to Li4Z2. Mn has four nearest neighbors in group-A and has one nearest neighbor in group-B. The bonding features of the alloys are compared to the ionic bonding in Li4Z2, and the tetragonal structure of cubic LiMnZ. The magnetic moments of these compounds ar…
Influence of alkylphosphonic acid grafting on the electronic and magnetic properties of La2/3Sr1/3MnO3 surfaces
2015
Self-assembled monolayers (SAMs) are highly promising materials for molecular engineering of electronic and spintronics devices thanks to their surface functionalization properties. In this direction, alkylphosphonic acids have been used to functionalize the most common ferromagnetic electrode in organic spintronics: La2/3Sr1/3MnO3 (LSMO). However, a study on the influence of SAMs grafting on LSMO electronic and magnetic properties is still missing. In this letter, we probe the influence of alkylphosphonic acids-based SAMs on the electronic and magnetic properties of the LSMO surface using different spectroscopies. We observe by X-ray photoemission and X-ray absorption that the grafting of …
Exploring room-temperature transport of single-molecule magnet-based molecular spintronics devices using the magnetic tunnel junction as a device pla…
2019
A device architecture utilizing a single-molecule magnet (SMM) as a device element between two ferromagnetic electrodes may open vast opportunities to create novel molecular spintronics devices. Here, we report a method of connecting an SMM to the ferromagnetic electrodes. We utilized a nickel (Ni)–AlOx–Ni magnetic tunnel junction (MTJ) with the exposed side edges as a test bed. In the present work, we utilized an SMM with a hexanuclear [Mn6(μ3-O)2(H2N-sao)6(6-atha)2(EtOH)6] [H2N-saoH = salicylamidoxime, 6-atha = 6-acetylthiohexanoate] complex that is attached to alkane tethers terminated with thiols. These Mn-based molecules were electrochemically bonded between the two Ni electrodes of an…
On the Theory of Domain Structure of Disordered Ferroelectrics
2009
We present a comprehensive analysis of domain structure formation in ferroelectric phase of incipient ferroelectrics with off-center dipole impurities like KTaO 3 :Li, Nb,Na. Our analysis is carried out on the base of effective free energy of disordered ferroelectrics, derived by us earlier. This free energy permits to apply the standard approach to domain structure calculation. Using coupled system of Maxwell equations with those obtained by minimization of above free energy, we calculate the physical characteristics of domain structure as functions of impurity dipoles concentration n. Our theory can be easily generalized for arbitrary temperature and crystal shape including thin films.
Parametric conversion in micrometer and sub-micrometer structured ferroelectric crystals by surface poling
2012
We report on recent technological improvements concerning nonlinear patterning of lithium niobate and lithium tantalate in the micrometer and submicrometer scales using surface periodic poling for ferroelectric domain inversion. The fabricated samples were employed for frequency doubling via quasiphase-matching both in bulk and guided wave geometries, including forward and backward configurations and wavelength conversion in bands C and L. We also investigated short-period quasiperiodic samples with randomly distributed mark-to-space ratios.
Multifunctional clickable and protein-repellent magnetic silica nanoparticles
2016
Silica nanoparticles are versatile materials whose physicochemical surface properties can be precisely adjusted. Because it is possible to combine several functionalities in a single carrier, silica-based materials are excellent candidates for biomedical applications. However, the functionality of the nanoparticles can get lost upon exposure to biological media due to uncontrolled biomolecule adsorption. Therefore, it is important to develop strategies that reduce non-specific protein-particle interactions without losing the introduced surface functionality. Herein, organosilane chemistry is employed to produce magnetic silica nanoparticles bearing differing amounts of amino and alkene func…