Multifunctional Magnetic Molecular Materials

Crystallographic evolution of lead batteries in real “in operando” conditions using wavelength-selective neutron imaging and tomography techniques

MagneticMole4 — Mon, 28 Jun 2021 12:30:06 +0000

PhD OPEN POSITION

Main thesis topic: To study the crystallographic evolution of lead batteries in real in operando conditions, using wavelength-selective neutron imaging and tomography techniques, in order to increase their energy efficiency. The work will involve experiment design and development of new routines for quantitative image analysis. Experiments will be mainly carried out at the NIST Center for Neutron Research (NCNR, Gaithersburg, MD, USA).

Working framework: International Project leaded by INMA. Partners: Exide Technologies (multinational company) and NIST. Funded by the private body Consortium for Battery Innovation (CBI).

Profile of the candidate: Masters in Physics, Chemistry, Material Science, Engineering or similar. Good command of English, teamwork skills and learning capacities. Basic background in neutron scattering, crystallography, image analysis and MATLAB programming would be ideal but not essential.

Terms of contract: Work contract extended annually up to 4 years. The annual gross salary will be divided into 14 payments of 1.730 €. Medical insurance (Spanish public health system) and other social benefits for the Consejo Superior de Investigaciones Científicas (CSIC) employees.

Starting date: Second semester in 2021 (negotiable). Further information: Send a resume/CV and your exam scores (Degree and Masters) to Dr. Ángel Larrea (alarrea@unizar.es) or to Dr Javier Campo (javier.campo@csic.es)

Thesis supervisors: Ángel Larrea and Javier Campo

Related links:

Project webpage in CBI

Project webpage in NIST

See differently with neutrons

CSIC

U. Zaragoza

Thermometry at the nanoscale

MagneticMole4 — Mon, 30 Nov 2020 14:04:15 +0000

In response to the need of real-time non-contact thermometry with submicron resolution and high sensitivity readout in Nanotechnology in general and NanoBioMedicine in particular, the group has developed a new technology based on the use of luminescence nanosensors and a fluorescence detection instrument. The nanoprobes consist of ad hoc designed copolymers bearing lanthanide luminescence complexes. The detection instrument consist of a fluorescence microscope coupled to a beam splitter, a CMOS camera and a software that transform the emission of the nanosensors into temperature images in real time. This system is able to map the temperature in the interior of cells and the local temperature of nanoheaters coated with the designed copolymers. The instrument is actually used in studies of mitochondria activity, and local hyperthermia therapy. Moreover, the group has also developed an alternative temperature scanning method using similar molecular temperature sensors and a double optical fibber probe to determine the temperature on surfaces (i.e. chips). The molecular thermometers are spread on the surface as paint or as self-assembled monolayer.

SpINS-XtremeD

MagneticMole4 — Thu, 26 Nov 2020 09:50:10 +0000

Científico de Instrumento

Oferta de Empleo:

El Instituto de Nanociencia y Materiales de Aragón busca 1 Científico de Instrumento para trabajar en el Institut Laue Langevin (ILL) en Grenoble, Francia, en el futuro difractómetro de neutrones térmicos para monocristales y polvos XtremeD adaptado para trabajar en condiciones extremas de alto campo magnético y altas presiones y operado por el CSIC en régimen de CRG (Collaborating Research Group).

Titulación:

Doctorado en Física, Química, Geología, Ciencia de Materiales o equivalente.

Experiencia y conocimientos:

Se tendrá en cuenta, particularmente, la experiencia previa en técnicas neutrónicas. También se considerarán los conocimientos en; técnicas de difracción en general, cristalografía, química o física del estado sólido, altas presiones, y magnetismo. Asimismo, se valorará la experiencia post-doctoral previa del candidato, especialmente si esta se ha desarrollado en los campos citados anteriormente. La experiencia o el interés demostrados en el diseño de instrumentación científica avanzada serán también considerados muy positivamente.

Funciones:

Los candidatos elegidos trabajarán en el marco de los convenios firmados por el CSIC y el ILL para la explotación del citado difractómetro del ILL. En su trabajo los candidatos realizarán labores de coordinación, preparación y realización de experimentos en los citados instrumentos y deberán trabajar en estrecha colaboración con la comunidad científica española de usuarios de técnicas de neutrones. Los candidatos podrán desarrollar también su propio proyecto de investigación.

Duración y salario:

El contrato laboral será realizado por el CSIC a través del Instituto de Nanociencia y Materiales de Aragón y el lugar de trabajo será el ILL en Grenoble (Francia). La duración inicial del contrato será de 12 meses con posibilidad de renovación hasta un total de 36 meses. El nivel de salario será competitivo y reflejará la experiencia de los candidatos elegidos.

Los interesados deberán enviar por correo electrónico, antes del 9 de Diciembre de 2020, un ejemplar de su Curriculum Vitae junto a una carta de motivación y el nombre de dos personas de referencia a:

Dr. Javier CAMPO

Instituto de Nanociencia y Materiales de Aragón

Facultad de Ciencias – C/ Pedro Cerbuna 12 – 50009 Zaragoza

Tel: +34 976 76 27 42 e-mail: javier.campo@csic.es

Calorimetry goes nano

MagneticMole4 — Sun, 25 Oct 2020 22:10:40 +0000

Thermodynamic measurements give a great deal of information on fundamental properties, providing direct and quantifiable insight into, e.g., densities of state and phase transitions. Many interesting materials are obtained in the form of sub-microgram single-crystals, thin films or even grafted monolayers. The mass of these samples is extremely small and so is their heat capacity. Therefore, this makes conventional calorimeters unsuitable.

Using micromachining technology, we fabricate and develop different types of membrane-based nanocalorimeters. They can be operated in either modulation (AC) calorimetry or relaxation calorimetry, over a broad range of temperatures and applied magnetic fields. We employ our devices for challenging studies on magnetic systems, including spin-crossover compounds and molecules for applications in quantum information and magnetic refrigeration on a chip.

Top: Photograph of a calorimeter based on a Si (left) or Si₃N₄ (right) membrane with a ca. 100 nanogram single-crystal of [Fe_xM_1-x(btr)₂(NCS)₂]·H₂O (highlighted by the arrow). Sample is a courtesy of Kamel Boukheddaden.

Top left: Temperature response of the calorimeter to a heat pulse. Blue line is the fit to an exponential relaxation. Top right: Experimental zero-field heat capacity. Data are collected with a homemade calorimeter, based on a Si₃N₄ membrane, for a ca. 100 nanogram single-crystal of [Fe_xM_1-x(btr)₂(NCS)₂]·H₂O. Sample is a courtesy of Kamel Boukheddaden.

Top left: Photograph of a calorimeter based on a Si₃N₄ membrane with a ca. 5 nanogram single-crystal flake of FePS₃ (highlighted by dotted lines). Top right: Its experimental zero-field AC heat capacity that shows antiferromagnetic ordering (see the peak heat capacity in the inset). Sample is a courtesy of Samuel Mañas.

The team

Giulia Lorusso, Juan José Morales, Michel Castro, and Marco Evangelisti.

Grinsparg-Wilson fermions

MagneticMole4 — Wed, 14 Oct 2020 21:45:57 +0000

OBJETIVO

En este trabajo de fin de master se pretende adaptar la formulación de fermiones de Ginsparg-Wilson y sus consecuencias (por ejemplo el “teorema del índice”), desarrolladas en el área de la física de altas energías, al área reciente de los materiales topológicos. En el desarrollo se combinarán ideas matemáticas de topología y teoría de operadores con teoría cuántica de campos y conceptos de física de estado sólido.

CONCEPTOS QUE SERÁN ADQUIRIDOS:

topología algebraica, teoría de operadores
teoría cuántica de campos, grupo de renormalización, realización de simetrías, anomalías
ecuaciones diferenciales, algebra numérica
propiedades topológicas de los materiales

TAREAS

Bibliografía y estudio de propiedades topológicas de la materia, fermiones de Dirac y de Weyl en potenciales periódicos, fermiones de Ginsparg-Wilson, anomalías y teorema del índice
Estudio de la viabilidad de la implementación de fermiones de Ginsparg-Wilson para describir excitaciones fermiónicas en materiales
calculos analiticos y numericos

More information please contact Victor Laliena and Javier Campo

Magnonics with chiral magnets

MagneticMole4 — Wed, 14 Oct 2020 21:30:40 +0000

Introduction.

The chiral solitons stabilized by the DMI are very interesting because they can present advantages over skyrmions, since their movement is not gyro-tropic and they will be easier to control. Moreover, it is interesting to elucidate the advantages that they can present with respect to the domain walls. On the other hand, the theoretical techniques used to study the dynamics of magnetic structures are of two types: i) the introduction of a few collective variables to describe the structure and ii) the numerical resolution of the LLG equation. In the first case, a generalization of the method of collective variables recently developed is used, and it will be necessary to deduce the equations that govern the dynamics of collective variables. For linear structures such as domain walls and chiral solitons in two dimensions (thin films) the center of the structure forms a line and its dynamics can be described by an elastic line model. The rest of the collective variables (for example, the width) could qualitatively change the dynamics of the elastic line.

Objectives

Main objective is the study of the response of solitons in monoaxial chiral magnets to applied magnetic fields and spin transfer torques induced by polarized electric currents, by means of effective models of collective variables and numerical simulations of the Landau-Lifshitz-Gilbert equation (LLG)

Task to be developped

Mainly numerical techniques will be used, although it will also be necessary to apply analytical techniques. In particular, numerical resolution techniques of initial value problems will be used in deterministic and stochastic differential equations (explicit or implicit methods) and border value problems (relaxation methods). The analytical techniques will be of a perturbative nature and will be applied to cases where external forces are weak.

More Information

Please contact Victor Laliena or Javier Campo.

Further information is also available on this website:

https://erasmusintern.org/traineeship/soliton-dynamics-monoaxial-chiral-magnets

Spin densities in organic magnets

MagneticMole4 — Wed, 14 Oct 2020 20:47:32 +0000

Introduction. In our work we are focused in the development of new types of triangular spin networks employing highly isotropic organic radical spins. By rational designing of organic tri-radicals, an equilateral triangle of S = 1/2 spins can be constructed. Since the anisotropy of the g-factor of these nitroxide-based compounds is less than 0.5 %, the electron spins are fully isotropic. These would be the best realizations of fluctuating spin system, which will show novel collective phenomena. In this context we have succeeded in synthesizing the new compounds F4BIPBNN , which forms a distorted Honeycomb lattice. The magnetic and thermal properties were examined in magnetic fields and the magnetic field versus temperature phase diagram is determined (1)

The goal of the present TFM is double. On one side we are interested in the exploration of the magnetic phase diagram of F4BIPBNN by the determination the magnetic structure of below 0.4K. For this goal we will collect data of neutron diffraction in deuterated single crystals of F4BIPBNN and, as a first step, we will model the different magnetic structures allowed by the symmetry in the organic radical. On the other hand, we will determine with polarized neutrons diffraction the spin density in the radical. The real experimental spin density determination at F4BIPBNN will help us to validate the MO and Broken Symmetry calculations and to have another independent experimental estimation of the intra and inter molecular interactions. However, previously to the experiment, we will simulate the real experiments taken into account the theoretical spin density obtained by DFT calculations.

Concepts that will be acquired:

Single crystal diffraction
Group theory and magnetic crystallography
Neutron scattering

Task to be developped:

Bibliography on the subject.
magnetic structure simulation
spin density modelization

More information contact with Javier Campo

(1) Naoki Amaya, et al Journal of the Physical Society of Japan 86, 074706 (2017)