Offres de Post-doctorat

Self-oriented hexaferrites for self-biased circulators and isolators

Research laboratory : Groupe de Physique des Matériaux (GPM), Université de Rouen Normandie, France, ERMMA group (Magnetic Materials for Applications)

Dates : January 2022 for a period of 12 months

Requirements : Successful candidate will have a Ph. D in Materials Science, Chemistry, Physics, Chemical Engineering or a closely allied field and have a strong background in materials characterization

 

Details :

 

Hexagonal ferrites are a class of magnetic materials that potentially can play an important role in the propagation of electromagnetic waves in microwave and millimeter waves devices. These components are an important part of diverse range of commercial and military applications, including radar, wireless and satellite communications. In particular, a key component of radar electronics is the circulator. Ferrite circulators are passive components used to distribute signals in a three-port radar or wireless communication system. By proper design, it can be made that one port becomes “invisible”, or in a microwave engineer’s word, isolated, from another port. However reversely the port can see a through path to that port without problem. This is the non-reciprocal property of the circulator. A long-standing problem with conventional ferrite circulators is the permanent magnets placed above and/or below ferrite pellets to provide the necessary biasing magnetic field for operation. Rare Earth Elements are used in the production of magnets, which exposes manufacturers and systems integrators to supply chain risks. Due to their relatively large weight, permanent magnets tend to detach in high shock or vibration environments causing system failures. This issue is particularly acute in radar systems that require thousands, or even tens thousands, of circulators. The elimination of these magnets has long been the goal of device manufacturers.

Recently, a new substrate has been developed that do not require permanent magnets [1]. In such self-biased circulators, the pellet is created by aligning the magnetic grains of hard hexaferrite by applying a magnetic field and then processing the material at high temperature to create a dense compact which act as a magnet itself.

 

The aim of this project, funded by the Institut Carnot ESP (Energie et Systèmes de Propulsion), is to prepare and characterize disks made of polycrystalline hexaferrite with platelet shape obtained by hydrothermal synthesis [2]. The advantage of this type of powder is that, due to their shape, the alignment of the grains is obtained by pressing only and the application of a magnetic field during the creation of the pellet is not necessary [3]. This would simplify the manufacture of such pellets.

 

The candidate will perform the syntheses of the powders and the pellets, and he/she will be in charge of characterization by X-Ray diffraction, Scanning Electron Microscopy, 57Fe Mossbauer Spectroscopy and Squid Magnetometry. Knowledge in microwave measurements would be appreciated.

This study will be performed in collaboration with IRSEEM (Research Institute for Embedded Electronic Systems).

 

Interested and qualified persons should submit a letter describing their background and specific experience and capabilities, full curriculum vitae, copies of recent publications, and the name, e-mail address of at least one reference.

 

 

[1] https://www.mtmgx.com/

[2] M. Jean et al., J. Alloys Compd, 496 (2010) 306-312

[3] M. Saura-Muzquiz et al., ACS Appl. Nano Mater., 1 (2018) 6938-6949

 

Contacts :

Associate Professors Virginie NACHBAUR (virginie.nachbaur@univ-rouen.fr), Samuel Jouen (samuel.jouen@univ-rouen.fr) and Malick Jean (malick.jean@univ-rouen.fr)

 

Closing date for application : 15/12/2021

Position Sensitive Detector for the development of Atom Probe Tomography

Subject of the postdoc :

The tomographic atom probe is a quantitative nano-analysis tool that allows us to image in three dimensions a small volume of a metal sample at the atomic scale. This instrument was developed in the lab 30 years ago. It is now an indispensable tool in materials science whether in the fields of micro-electronics (development of integrated system, physical cause analysis of their failures...), energy and metal materials industrial purposes (automotive, aeronautics, nuclear industry ...). This instrument is commercialized by CAMECA (about 100 machines installed worldwide in universities or private research centers).

The basic principle of this technique is the field evaporation of atoms of a sample, and detection of these emitted particles in the form of ions by a high-performance detector. The detector converts the impact of an ion (a few keV kinetic energy) into a coordinate (X, Y) and flight time. Since 1993, several generations of detector for atom probe has been developed by the instrumentation team, with each generation a technological leap that allowed improving significantly the performances of the instrument.

This post-doctoral research project (collaboration with CAMECA) proposes
1/ Development of new Tomographic Atom Probe position sensitive detectors (PSD), with the integration of a fast and efficient digitalization of signals and related signal deconvolution and timing combination algorithms. The limitations in term of multihits / data throughput / data quality will be first evaluated on test PSDs. From these results, a setup will be developed in close collaboration with CAMECA and GPM teams, to integrate the best system to a commercial AP.
2/ Development of Carbon Foil enhanced position sensitive detectors (CFE-PSD). Optimization of the system to enable an increase in detection efficiency and to improve the will be done. The design of the CFE-PSD will be adapted to increase the efficiency of collection and multihit capabilities. Hit finding and association algorithm will be improved.

 

Candidate profile:

The candidate (man or woman) must have a Phd in physics, electronics, instrumentation or related disciplines and a keen interest in academic research in an industrial development environment. A possible experience (projects, internships, etc ...) in the field of electronic design, and scientific instrumentation would be appreciated. The candidate will be supervised by specialists in scientific instrumentation, physics, and materials science. The candidate must have an excellent level in English (frequent meetings with our industrial partner).


Contact: francois.vurpillot@univ-rouen.fr
Laboratory: GPM / UMR CNRS 6634
Location: Instrumentation Dep. UMR CNRS 6634 Technopole du Madrillet, Institut des materials, 76800 Saint Etienne du Rouvray

Industrial partner: CAMECA (Genevilliers / France and Madison / USA)
Employer Institution: University of Rouen (Salary dependant of the applicant experience) Duration : 2 years. (from October 2021 to September 2023)

Bio samples encapsulation and shaping for atom probe tomography

The GPM laboratory is inviting applications for a postdoctoral position in the field of biosamples encapsulation and preparation for 4D imaging. The position is funded within project Bio-TAP which gathers experts in light-matter interactions in the ultrafast regime, laser physics and 3D microscopy and atom probe tomography and biosamples isolation and encapsulation from the GPM, GlycoMev, CORIA and Envi laboratories at the university of Rouen. This multidisciplinary project aims at developing a novel high-resolution 4D microscopy platform by using THz-APT (atom probe tomography) instrument to image biomaterials.

This research will be developed at the Groupe de Physique des Matériaux (GPM) in collaboration with the laboratory of Glycobiology and Plant Extracellular Matrix at the University of Rouen FRANCE.

 

Qualifications and experience:

The applicant should hold a PhD in the fields of biology or applied physics, with experimental skills in electron microscopy and correlative microscopies. Experience in Focused ion beam milling/or cryo-microscopy will be appreciated.
The project involves the design and set-up of new methods for sample encapsulation and preparation as well as data collection and analysis within a collaborative project. The candidate should then have an affinity for working in multidisciplinary teams. He/She will indeed have an active role in this collaboration by interacting with the different partner laboratories.

Contact : Please submit your application (including a cover letter and a detailed CV) by e-mail

Pr Angela Vella : angela.vella@univ-rouen.fr

and Dr. Emmanuel Cadel : emmanuel.cadel@univ-rouen.fr

 

 

3D microscopy of energy materials by THzAtom Probe Tomography

This research will be developed at the Groupe de Physique des Matériaux (GPM) in collaboration with the department of Optics & Lasers of CORIA at the University of Rouen FRANCE.

Description of the project:

Activities at the GPM laboratory are focused on investigating the link between material properties and their features at the nanometer scale. One of the laboratory’s teams is the “advanced instrumentation team” (ERIS) where the Tomographic Atom Probe was developed in the 1990s. Today, ERIS is one of the world’s leading teams in the development of laser-assisted 3D atom probes, in particular concerning field evaporation processes and laser matter interaction at nanoscale.

The recent development of laser-assisted atom probe tomography (ATP) opened the instrument to the analysis of semi-conductors and insulators. However, light absorption leads to strong thermal effects which are seriously prejudicial to the performance of theinstrument. To overcome these limitations, we have developed a novel ATP instrument using low-energy photon THz pulses instead of ultraviolet lasers. The objective of this position is to evaluate the performances of the new instrument on energy materials.

Qualifications and experience:

The applicat will work to the optimization of the ultrafast THz source as well as to the analysis of different energy materials (semi-conductors multilayers, quantum wells, quantum dots,..) in order to prove the capabilities of the new illumination conditions.

The ideal applicant for this post-doc position should hold a PhD thesis in the fields of ultrafast optics, THz science, field emission and/or would have already worked with atom probe. He/She should be able to work independently and in team. His work will take place at GPM laboratory in collaboration with the Optics&Laser team of CORIA.

 

Applicants are requested to send CV and recommendation/motivation letters to the following address: https://bit.ly/356zg9B

Caractérisation électrique des pièges des transistors à haute mobilité électronique en Nitrure de Gallium

Le projet « Plateforme de Caractérisations Electriques jusqu’aux échelles Nanométriques » (PLACENANO) est financé par la Région Normandie via les Réseaux d’Intérêts Normands (RIN RECHERCHE) et l’Union Européenne avec le Fonds Européen de Développement Régional (FEDER). Le CDD d’une durée de 4 mois commencera au plus tôt.


Profil des candidats :

Le candidat, titulaire d’une thèse doit avoir une formation dans le domaine de l’électronique avec des connaissances sur les transistors de puissance. Un candidat ayant des qualités d’expérimentateur est souhaitable. Une expérience dans le domaine de la microscopie peut être un plus mais n’est pas obligatoire. Il devra être capable également d’approfondir les aspects de la simulation physique des composants.

Pour répondre à cette offre, fournir CV et lettres de recommandations/motivations à :

olivier.latry@univ-rouen.fr

3D Atomic Resolution Electron Tomography for Embryonic Zeolites

In the framework of the 3D NanoZet project, a post-doc position is available at the GPM laboratory for TEM characterization of ultra-small porous zeolites designed for petro-chemistry.

The post-doctoral fellow will be in charge with the realisation of the 2D and 3D characterization using an analytical double corrected TEM installed on the Genesis platform at GPM. He/she will participate to the definition of experimental protocols for the 3D characterization of beam-sensitive materials, in terms of data acquisition and treatment.  The candidate should have a phD in materials sciences, applied physics or chemistry, or a related discipline. A fluent knowledge of English and/or French is a pre-requisite. The successful candidate will be highly motivated, creative, with demonstrated abilities to work in a collaborative environment. Prior experimental and practical background in Transmission Electron Microscopy and electron tomography will be strongly appreciated.

Applicants are requested to send CV and recommendation/motivation letters to the following address: 

simona.moldovan@univ-rouen.fr

Proposition of a Post-doc position on TEM and STEM-EELS/EDX study of magnetic nanostructures

In the framework of the MAGMA project, a post-doc position of 12 months is available at the GPM laboratory for advanced TEM characterization of such nanostructures. The post-doctoral fellow will be in charge of the sample preparation, the Cs-corrected Transmission Electron Microscopy (Jeol ARM) observations and STEM-EELS/EDX analyses to obtain atomic maps of the magnetic dopants inside the semiconducting matrix. The results will be compared to those recently obtained by other advanced characterization techniques such as tomographic atom probe and 57Fe Mössbauer spectroscopy. Therefore, the candidate should have a strong experience in TEM and STEM-EELS/EDX including sample preparation by FIB SEM, with good background in Material Science. During his position, the post-doctoral fellow will be able to benefit from the whole advanced instrumental facilities for sample preparation and TEM analyses of the GPM laboratory in order to reinforce his skills in this field.

 

Applicants are requested to send CV and recommendation/motivation letters to the following address: 

jean.juraszek@univ-rouen.fr

MICROstructural investigations of low alloyed steel FORging

To support the project MICROFOR “MICROstructural investigations of low alloyed steel FORging”funded by SCK Studiecentrum voor Kernenergie/Centre d’Etude de l’Energie Nucléaire (Belgium), the French Research laboratory « Groupe de Physique des Matériaux » (Materials Physic Group) is looking for a Post Doc researcher.

 

Candidate will :

  • support the team in charge of the MICROFOR project and will use Atom probe Tomography and electron microscopies (SEM and TEM);

  • participate to the study of materials from SCK CEN

  • conduct sample preparation and run analyses with state of art instruments LEAP 4000, TEM JEOL 200KV.

  • Participate to the technical workshop related to the MICROFOR project

  • Share his/her activities with other collaborators involved in the project

  • Report frequently technical advances to superior coworkers (GPM and SCK)

  • Contribute to the global organization and functional activities of the GENESIS Platform

Applicants are requested to send CV and recommendation/motivation letters to the following address:

philippe.pareige@univ-rouen.fr

Post doc: Analyse microstructurale et thermique de complexes polymères

Le poste est un contrat de 1 an dans le cadre d'un projet FEDER et Région NORMANDIE en relation avec un industriel normand de l’aéronautique et un consortium de laboratoires publiques et privés. Le sujet est confidentiel et concerne la caractérisation et l'optimisation de complexe polymère.

Profil des candidats :

Doctorat et/ou post doc en sciences des matériaux, spécialisé en matériaux polymères
propriétés physiques, propriétés de surface, vieillissement physico-chimique
maitrise de : DSC, TMDSC, BDS, DMA, TGA, Essai mécanique de base, DRX, Microscopie Electronique.

Pour répondre à cette offre, fournir CV et lettres de recommandations/motivations à :

eric.dargent@univ-rouen.fr