Search results for "antiferromagnetic"
showing 9 items of 39 documents
Electronic Structure Modulation in an Exceptionally Stable Non-Heme Nitrosyl Iron(II) Spin-Crossover Complex
2016
The highly stable nitrosyl iron(II) mononuclear complex [Fe(bztpen)(NO)](PF6)(2) (bztpen=N-benzyl-N,N',N'-tris(2-pyridylmethyl)ethylenediamine) displays an S=1/2 S=3/2 spin crossover (SCO) behavior (T-1/2=370 K, Delta H= 12.48 kJmol(-1), Delta S=33 JK(-1) mol(-1)) stemming from strong magnetic coupling between the NO radical (S=1/2) and thermally interconverted (S=0 S=2) ferrous spin states. The crystal structure of this robust complex has been investigated in the temperature range 120-420 K affording a detailed picture of how the electronic distribution of the t(2g)-e(g) orbitals modulates the structure of the {FeNO}(7) bond, providing valuable magneto-structural and spectroscopic correlat…
A heteropentanuclear oxalato-bridged [ReIV 4GdIII] complex: synthesis, crystal structure and magnetic properties
2012
The compound (NBu 4) 5[Gd III{Re IVBr 4(μ-ox)} 4(H 2O)]·H 2O (1), with intramolecular antiferromagnetic coupling, is the first Re(iv) system incorporating a 4f ion. © 2012 The Royal Society of Chemistry.
Terahertz electrical writing speed in an antiferromagnetic memory
2018
The speed of writing of state-of-the-art ferromagnetic memories is physically limited by an intrinsic gigahertz threshold. Recently, realization of memory devices based on antiferromagnets, in which spin directions periodically alternate from one atomic lattice site to the next has moved research in an alternative direction. We experimentally demonstrate at room temperature that the speed of reversible electrical writing in a memory device can be scaled up to terahertz using an antiferromagnet. A current-induced spin-torque mechanism is responsible for the switching in our memory devices throughout the 12-order-of-magnitude range of writing speeds from hertz to terahertz. Our work opens the…
Nanosession: Spin Tunneling Systems
2013
Coexistence of ferro- and antiferromagnetic interactions in a metal-organic radical-based (6,3)-helical network with large channels.
2005
A metal–organic open-framework with an unprecedented (6,3)-helical topology, large channels and mixed ferro- and antiferromagnetic interactions has been synthesized using a three-connecting tricarboxylic polychlorotriphenylmethyl radical and Co(II) ions. Lloret Pastor, Francisco, Francisco.Lloret@uv.es
Polarisation dependent Raman study of single-crystal nickel oxide
2011
Abstract The magnetic domain structure and Raman scattering have been studied in NiO single-crystals with three different (100), (110) and (111) orientations. Twin-domain structure was observed in NiO(100) and NiO(110) single-crystals using cross-polarized optical microscopy. We found that the ratio of the two-magnon (at 1500 cm−1) to the two-phonon (2LO, at 1100 cm−1) Raman bands intensity is sensitive in a particular way to the type of the twin-domain pattern.
New Route to Polynuclear Ni(II) and Cu(II) Complexes with Bridging Oxime Groups That Are Inaccessible by Conventional Preparations
2019
A series of new polynuclear complexes of divalent Ni and Cu with 2-cyano-2-oximino-acetic acid (later AACO2-) were obtained as the result of the ligand modification reaction in the process of complexation, using 2-cyano-2-oximino-acetates such as methyl- (later as MeCO), and ethyl- (as ECO later on). Synthesized compounds were characterized by spectroscopic methods, thermal analysis, magnetochemistry, and X-ray crystallography. Crystal data revealed the formation of the dimeric [Ni(AACO)(H2O)3]2·H2O (1), trimeric K2[Ni3(AACO)4(H2O)4]·4H2O (2), and K2[Cu3(AACO)4(H2O)4]·4H2O (3) complexes, with bridging NO-groups cyanoxime dianions. In the latter two compounds, the AACO2– anions adopt cis-arr…
Synthesis and characterization of new coordination compounds by the use of 2-pyridinemethanol and di- or tricarboxylic acids
2021
The development of synthetic approaches towards new coordination polymers has attracted significant interest due to their fascinating physical properties, as well as their use in a wide range of technological, environmental and biomedical applications. Herein, the initial combination of 2-pyridinemethanol (Hhmp) with 1,4-benzenedicarboxylic acid (H2bdc) or 1,3,5-benzenetricarboxylic acid (H3btc) has been proven a fruitful source of such new species providing access to five new coordination compounds, namely [M2(Hbtc)2(Hhmp)4]·DMF (M = CoII, 1·DMF;NiII, 2·DMF), [Ni(bdc)(Hhmp)2]n·4H2O (3·4H2O), [Zn2(bdc)(hmp)2]n·DMF (4·DMF) and [Fe3(bdc)3(Hhmp)2]n (5). 4·DMF and 5 are the first metal–organic …
Nuevos materiales moleculares de hierro(II) multipropiedad basados en el fenómeno de transición de espín
2017
En esta Tesis Doctoral se presenta la síntesis y caracterización de una serie de materiales multifuncionales de FeII que tienen como denominador común el fenómeno de transición de espín (TS). El objetivo general es investigar sinergias entre la TS y otra propiedad fisicoquímica mediante el estudio de su estructura molecular y sus propiedades magnéticas y calorimétricas, entre otras. En el Capítulo Uno se exponen los conceptos más relevantes del fenómeno TS en el cual los centros TS experimentan una conversión de espín HS↔LS (HS: estado de espín alto, LS: estado de espín bajo) en respuesta a un estímulo externo tal como temperatura, presión, luz o la presencia de analitos. En particular, una…