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Offers : 50

RF characterization of magnetite powders

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offer n° IMEPLaHC-12172019-RFM

                                                              

   IEPT or Master’s Internship – 2020
         RF characterization of magnetite powders  

 

Keywords :
Magnetic particles, RF characterization of materials, materials properties, electromagnetic and physical modeling

Lab :
Institut de Microélectronique, Electromagnétisme et Photonique – Laboratoire d’Hyperfréquences et de Caractérisation
IMEP-LaHC, Minatec – 3, parvis Louis Néel, BP 257, 38 016 GRENOBLE Cedex 1
IMEP-LaHC is a public research unit (CNRS/Grenoble INP/UGA/USMB) of 180 people involved in several research topics such as micro and nano-electronics, photonics and microwaves.

Duration :
6 months

Directors :
Pr. VUONG Tan-Phu, tan-phu.vuong@grenoble-inp.fr, 04.56.52.95.65
Pr. XAVIER Pascal, pascal.x avier@univ-grenoble-alpes.fr , 04.56.52.95.69

Company :
LE BOUTEILLER Philippe, philippe.le-bouteiller @ hymagin.com

1. Context
HYMAG’IN produces an iron oxide powder, magnetite, and wishes to market it for various applications using its magnetic properties. HYMAG’IN seeks to characterize the intrinsic magnetic properties of its products, but also the properties of materials prepared by incorporating magnetite powder at different charge rates into clay, epoxy resin, paint and other matrices. Complex permeability is one of these properties in frequency ranges from MHz to a few GHz.
HYMAG’IN produces different types of magnetites, which differ from each other in their physico-chemical properties: distribution of sizes, shapes, chemical compositions. These various parameters are likely to impact the magnetic properties of the powders and materials in which they are incorporated.
By measuring the magnetic properties of different powders, HYMAG’IN therefore wishes to understand the impact of these different parameters and thus be able
to answer questions such as: How to optimize magnetite and/or formulation to maximize permeability?
Finally, HYMAG’IN wishes to compare the properties of its products with other materials already used in the applications under consideration, such as ferrites of different types. Comparative measurements must therefore be carried out with commercial products, powders or materials already formulated.
The IMEP-LaHC laboratory is providing its expertise and characterization resources to set up this study.
HYMAG’IN provides external support for the completion of this internship provided by Philippe Le Bouteiller.

2. Purpose of the internship
The internship will cover the following aspects:

  • Bibliography and theoretical approach to the magnetic behaviour of magnetite;
  • Evaluation of the feasibility and relevance of direct measurement on powders;
  • Implementation of measurement protocols on materials incorporating magnetite powders, and on powders directly, if necessary;
  • Performing measurements: samples of different magnetites, and materials at different charge rates;
  • Comparative measurements with materials already on the market: benchmark ;
  • Reflection on possible applications in the fields covered by the laboratory: electronics, space.

Please email your application (CV and cover letter) to the Directors indicated above

  • Keywords : Engineering science, Electronics and microelectronics - Optoelectronics, FMNT, IMEP-LaHc
  • Laboratory : FMNT / IMEP-LaHc
  • CEA code : IMEPLaHC-12172019-RFM
  • Contact : pascal.xavier@univ-grenoble-alpes.fr

Improvement of the determination of the physical profile of a soil, resulting from a measurement with a radiofrequency probe, by an optimized inverse calculation and machine learning

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offer n° IMEPLaHC-1202019-RFM


IEPT or Master’s Internship – 2020

Title : Improvement of the determination of the physical profile of a soil, resulting from a measurement with a radiofrequency probe, by an optimized inverse calculation and machine learning


Keywords:
Machine learning, Databases, electromagnetism, material characterization, physical models

Location :
IMEP-LaHC
Minatec – 3, parvis Louis Néel, BP 257, 38 016 GRENOBLE Cedex 1

Our lab is a joint research unit (CNRS/Grenoble INP/UGA/USMB) of 180 people whose research topics concern micro and nanoelectronics, photonics and microwaves.
The team will be composed of P. Xavier, Professor of the UGA, D. Rauly and E. Chamberod,Assitant Professors of the UGA.

Supervisor :
XAVIER Pascal, pascal.xavier@univ-grenoble-alpes.fr, 04.56.52.95.69 or 06.45.36.22.65

Candidate profile :
five years of higher education in computer science or applied mathematics.

1. Context and objectives
The innovative project DAMP (Device for the Analysis of Materials Profile) carried out by our laboratory is in the process of maturing with the Linksium Technology Transfer Acceleration Company (SATT). The aim is to develop an invasive and local hardware and software solution (radiofrequency probe equipped with commercial sensors), capable of physically characterizing liquid or solid media in depth with a resolution of the order of 1 cm. This probe is robust, easy to use and suitable for all environments. The technique used is fast, simple and inexpensive: it combines the advantages of two competing current technologies.
Our team has three applications in mind: the characterization of snow cover (height, density…) to anticipate the filling of EDF dams or prevent avalanches, smart irrigation of agricultural plots or input monitoring, monitoring the humidity level of buildings and structures. In the long term, a licence transfer is planned in the partner companies.

2. Purpose of the internship
The work will focus on processing the signals recorded by the probe and improving the physical modelling of environments. In this context, we offer a 4 to 5 month internship at Bac+5 level.
Based on an existing prototype and measurements made on site, the trainee will:

  •  program the software tool allowing, by a reverse calculation and optimization method, to go back to the physical parameters of the sections detected for each medium.
  • develop a database containing data from measurements made on model and real environments (depending on the applications)
  • test an automatic learning procedure to improve the accuracy of identifying the type of medium and measuring physical parameters.

As the DAMP project aims to enter the incubation phase in 2020, it will be appreciated if the candidate has a taste for adventure and is motivated by the opportunity to get involved in a marketing project.

Please send your applications (CV + cover letter) by email to pascal.xavier@univ-grenoble-alpes.fr

  • Keywords : Engineering science, Engineering science, Electronics and microelectronics - Optoelectronics, FMNT, IMEP-LaHc
  • Laboratory : FMNT / IMEP-LaHc
  • CEA code : IMEPLaHC-1202019-RFM
  • Contact : pascal.xavier@univ-grenoble-alpes.fr

Dispersion characterization of active glass waveguides

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offer n° IMEPLaHC-10292019-PHOTO

                                                      Master thesis -Master Recherche / PFE
                                                                             (5 to 6 month)
                                                     Dispersion characterization of active glass waveguides

IMEP-LaHC is working on integrated optics since a few decades and is one of the leading laboratories in the field of photonics on glass. A current objective of the team “PHOTO” of this institute is to develop mode-locked lasers using the glass photonics platform. Mode-locking can be obtained by different methods; the one we have selected uses a fast saturable absorber to form solitons in an optical cavity.

The method to produce those soliton is well known theoretically and requires balancing two effects that occur during the propagation of an optical pulse in the waveguide. The first one is dispersion that comes from both the material and the waveguide. The second effect is a non-linear phenomenon called “self phase modulation (SPM)”. Both phenomena need to be precisely characterized for a given technology in order to build an efficient mode-locked laser cavity. The present internship will focus on the precise measurement of the group dispersion of our waveguides.

Dispersion can be measured using an unbalanced Mach-Zehnder (MZ) interferometer whose arms are fabricated with the waveguides to be characterized [1]. A mask containing unbalanced MZ interferometers is already available at the laboratory, the rest is up to the intern !

The internship will be organized as follows:

  • Bibliographic study concerning the context (mode-locked lasers architectures, …) and the core subject (dispersion measurement in integrated waveguides)
  • Using the provided photolithography mask, fabricate MZ devices using the clean room facilities of the laboratory.
  •  Characterize the different MZ present on the chip (transmission spectrum).
  • Analyze the measured spectra, compare to theory and choose which device is best suited for measuring dispersion.

This internship thus requires a student with an inclination for experimental work (fabrication and characterization). Some knowledge about integrated optics and an experience with clean room environment will be appreciated.

This Master’s subject thesis is a preliminary work for a future PhD subject on the same topic, but could also lead to a PhD thesis on another subject within the PHOTO team of IMEP LaHC.

[1] Dulkeith, Eric, et al. “Group index and group velocity dispersion in silicon-on-insulator photonic wires.” Optics Express 14.9 (2006): 3853-3863.

Advisors:
Jean-Emmanuel BROQUIN,  broquin@minatec.grenoble-inp.fr
Lionel BASTARD,  lionel.bastard@grenoble-inp.fr

  • Keywords : Engineering science, Engineering science, Electronics and microelectronics - Optoelectronics, FMNT, IMEP-LaHc
  • Laboratory : FMNT / IMEP-LaHc
  • CEA code : IMEPLaHC-10292019-PHOTO
  • Contact : lionel.bastard@grenoble-inp.fr

Micro-heaters for integrated laser tuning

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offer n° IMEPLaHC-10282019-PHOTO

                                                           Master thesis – Master Recherche / PFE
                                                                               (5 to 6 month)

                                                              Micro-heaters for integrated laser tuning

IMEP-LaHC is working on integrated optics since a few decades and is one of the leading laboratories in the field of photonics on glass. A current objective of the team “PHOTO” of this institute is to fabricate carriers of GHz to THz frequencies for future telecommunication systems and THz spectroscopy. The carrier signal is produced by the interaction on a rapid photodetector of two integrated optics lasers fabricated on the same substrate.

Such a device has already been demonstrated in a previous PhD thesis carried out at IMEP-LaHC [1]. The GHz or THz frequency is fixed by the design of the laser cavities and cannot be modified once the device has been fabricated. This internship is dedicated to obtaining a variable-frequency output by varying the temperature of one of the lasers. This temperature variation will be achieved by integrating a micro-heater on the device.

There are two parts to this internship:

  1. The first task is to use the existing literature and Comsol simulations to design the thin metallic layer which will constitute the micro-heater. Simulations will also be used to predict the temperature increase on the waveguide and the tunability of the produced carrier that can be expected.
  2. The second task is to fabricate the micro-heaters in a clean-room environment. Electrical and optical characterizations of the fabricated heaters will then be carried out by the intern and compared with the expected behavior of the device.

This internship thus requires a student with an inclination for both simulations and experimental work. Some knowledge about integrated optics and an experience with clean room environment will be appreciated.

This Master’s subject thesis is a preliminary work for a future PhD subject on the same topic, but could also lead to a PhD thesis on another subject within the PHOTO team of IMEP LaHC.

[1] N. Arab, “Optique intégrée sur verre pour la génération de fréquences radio”, PhD Thesis at Grenoble-INP, http://www.theses.fr/2018GREAT102

Advisors:
Lionel BASTARD lionel.bastard@grenoble-inp.fr
Julien POETTE julien.poette@grenoble-inp.fr

  • Keywords : Engineering science, Engineering science, Electronics and microelectronics - Optoelectronics, FMNT, IMEP-LaHc
  • Laboratory : FMNT / IMEP-LaHc
  • CEA code : IMEPLaHC-10282019-PHOTO
  • Contact : lionel.bastard@grenoble-inp.fr

Micromagnetic study of a voltage controlled skyrmion chirality switch

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offer n° 191022-9

Skyrmions in thin films are spin textures across which the magnetization follows a cycloid with a unique sense of rotation, known as chirality. These specific magnetic patterns can be stabilized in various kinds of materials, and particularly in ultrathin trilayers with no inversion symmetry (e.g. heavy metal/ferromagnet/oxide) exhibiting simultaneously an interfacial interaction called Dzyaloshinskii-Moriya (DMI) and a strong perpendicular magnetic anisotropy (PMA). Since they are ideally topological solitons, skyrmions are currently attracting considerable interest both for the underlying physics and for their applicative potential. Their ability to be set in motion by electrical current opens the way to imagine them as dense storage data bits or magnetic logic operations. Furthermore, the possibility to tune magnetic interfacial properties by a gate voltage enables low power control of spintronic devices and provides a versatile, local and dynamic degree of freedom that can be implemented in innovative designs.

In this context, in collaboration with Institut Néel, we have recently shown that a gate voltage can not only switch skyrmions on and off but also tune the interface properties (PMA and DMI). The new mechanism leading to DMI revealed by our experiments allows expecting a control of DMI sign, which would lead to an inversion of the skyrmion’s chirality.

In this internship, we target to study by micromagnetic simulations the possibility to change DMI sign and to demonstrate voltage controlled skyrmion chirality switch. This breakthrough would open new possibilities for skyrmion manipulation, as a change of chirality would invert the direction of current-induced motion. It will also open new and rich physics on the dynamical control of the topology of these solitons.

  • Keywords : Mathematics - Numerical analysis - Simulation, spintronics, IRIG, SPINTEC
  • Laboratory : IRIG / SPINTEC
  • CEA code : 191022-9
  • Contact : liliana.buda@cea.fr
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