Magnetomechanical properties of skin-conformal magnetic field sensors

19 Mar 2024
Job Information

Organisation/Company

LSPM-CNRS Université Sorbonne Paris Nord

Research Field

Physics
Technology » Materials technology

Researcher Profile

Recognised Researcher (R2)
Leading Researcher (R4)
First Stage Researcher (R1)
Established Researcher (R3)

Country

France

Application Deadline

4 Apr 2024 - 22:00 (UTC)

Type of Contract

Temporary

Job Status

Full-time

Offer Starting Date

2 Sep 2024

Is the job funded through the EU Research Framework Programme?

Not funded by an EU programme

Is the Job related to staff position within a Research Infrastructure?

No

Offer Description

Context: Flexible or stretchable magnetic systems are increasingly being studied for technological applications in the field of spintronics. This particularly concerns the detection of magnetic fields  in novel applications like smart wearables and even smart skins. In these application scenarious, magnetic field sensors are applied to uneven surfaces such as human skin, requiring excellent conformity inaccessible with traditional rigid substrates. In this context, the deposition of high-performance magnetoresistive sensors (e.g., giant magnetoresistive, GMR), composed of ultrathin high-quality metal layer stacks on thin polymer foils, is crucial for these applications. Another important aspect is to properly control the magnetic properties of these stacks under mechanical stresses to anticipate their performance. Particularly, it is important to verify how possible damages (cracks, detachments) alter the magnetization reversal phenomena during magnetization cycles. In this context, the two institutes proposing this thesis work (HZDR and LSPM-CNRS) are developing complementary skills to address these challenges. HZDR has strong expertise in the fabrication of flexible or stretchable GMR sensors (deposition, substrate transfer, printing on polymer substrates), in studying their magnetoresistive properties under deformation, as well as in more applied aspects (electronic skins applications). On the other hand, LSPM-CNRS develops highly original techniques in in situ magnetometry and spectroscopies (under tension or flexion tests) as well as microscopic observation/modeling of damages and magnetomechanical effects to study the fundamental coupling between the magnetic and mechanical phenomena. Currently, there is still a lack of understanding of the interplay between crack/blister/wrinkle geometries and the magnetic properties of magnetoresistive sensors.

 

Objectives: Thus, the subject here proposes a study of the magnetic properties of multilayers [FM/M]x (to be defined), deposited on polymeric foils (Kapton, Mylar) or elastomer membranes (PDMS). We pursue a study of damages, their impact on magnetization cycles (by in situ MOKE magnetometry), and possible phenomena of reversibility under mechanical cycling (effects of crack closures, etc.). In addition to studying the geometric effects of stacking (thicknesses affecting the geometry of multifissuration) on these magnetomechanical properties, we will conduct in situ tests under imaging (MFM and MOKE) to study the evolution of magnetic domains under magnetic field (before and after multicracking) in order to interpret the possible modifications of magnetization cycles (local effects of fissures on the configuration of domains and their evolution). All of these observations will be interpreted to anticipate more applied aspects, such as the effect of damages on magnetoresistance curves. The PhD student will be also involved in the realization of magnetic field sensors (optical lithography, choice of the sensor layout, signal-to-noise characterization, etc.), applying appropriate sensor conditioning schemes to discriminate the useful magnetic field signals from parasitic mechanical deformations (patent of the HZDR team) and developing of new use-case scenarios for these mechanically stable magnetic field sensors for human-machine interfaces and magnetic soft robotics.

 

Position (start anytime after sept. 1st, 2024)

The PhD candidate will undertake several-month stays at each of the institutes depending on the ongoing experimental campaigns (HZDR: fabrication and basic characterization of magnetoresistance, development of conditioning electronics, realization of demonstrators; LSPM-CNRS: magnetomechanical characterization, in situ imaging, magnetomechanical modelling). Furthermore, they will be in a leading European environment and will be able to benefit from developments carried out at the French synchrotron (biaxial traction machine and in situ MOKE). Regular online meetings and in-person stays will be organized to exchange on the project achievements, experimental results and sharing of samples for complementary measurements. Net salary: about 1700/month.

Funding category: Autre financement public
ANR
PHD title: Doctorat de Physique
PHD Country: France

Requirements
Specific Requirements

Requirements: The candidate must have a Master 2 degree (Solid state physics, Materials Science). Good communication skills, scientific curiosity and affinity to the experimental work are of strong advantage.

Additional Information
Work Location(s)

Number of offers available

1

Company/Institute

LSPM-CNRS Université Sorbonne Paris Nord

Country

France

City

Villetaneuse

Geofield

Where to apply

Website

https://www.abg.asso.fr/fr/candidatOffres/show/id_offre/121366

Contact

Website

https://www.lspm.cnrs.fr/en/home/

STATUS: EXPIRED