Optimisation of LSMO based magnetoresistive sensors for ultimate sensing
HOST INSTITUTION
Centre national de la recherche scientifique-CNRS-GREYC (France)
PhD PROJECT DESCRIPTION
The objective of the PhD work will be to magnetically detect the activity of neurons in-vitro. The PhD student will join the CNRS-GREYC research laboratory in Caen (France) to work on the fabrication and conception of low-field magnetoresistive sensors from La0.7Sr0.3MnO3 (LSMO) thin films. A significant AMR (Anisotropic Magnetoresistive Effect) and a very low electrical noise level at low frequency make them suitable for the development of new all oxides magnetic sensors, as previously demonstrated in [L. Enger et al. ACS Applied Electronic Materials 2023 5 (2), 729-739
DOI: 10.1021/acsaelm.2c01096] with detectivity as low as 200 pT.Hz-1/2 at 310 K and 1 kHz (Figure 1).
The PhD work will involve optimising the magnetoresistive detection elements as well as the low-noise electronic conditioning system (Figure 2) and will include the following tasks :
(1) Explore different compositions of manganites and other ferromagnetic oxide materials. (2) Explore silicon substrates to fabricate the magnetoresistive sensors based on the epitaxial ferromagnetic oxide thin films. (3) Design sensors and external magnetic circuits to increase the detection capability. (4) Design polymeric surfaces to place the neurons close to the magnetoresistive sensors in in-vitro testing. (5) Evaluate the feasibility of the detection of magnetic activity of neurons in vitro.
The candidate will take part to the fabrication of the sensors using the clean room facility available in CNRS-GREYC and will have to make all electrical and magnetic characterization of the successive prototypes. He/she will use existing set-ups at GREYC such as photolithography equipments, magnetoresistance and low frequency noise measurement set-ups, magneto-optical Kerr effect microscope.
A three-month secondment to SAL (Silicon Austria Labs, Villach, Austria) is planned for the modelling and design of sensors and magnetic circuits to be integrated into sensors and/or polymer structures. Another 3-month secondment is planned to IMDEA (Instituto Madrileño de Estudios Avanzados en Nanociencia, Madrid, Spain), for the design and production of the polymer materials to be placed between the magnetoresistive sensors and the neurons.
Several 1-2 weeks of experiments are planned to be performed at SISSA (Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy) for in vitro testing of magnetic neuron detection.
Figure 1: Measured detectivity at 310 K for different bias voltages in a 500 µm2 Wheatstone bridge patterned in 45 nm thick LSMO films on vicinal substrates.
Figure 2: Multidisciplinary nature of the PhD work, including Microfabrication, Sensor design & Magnetism, Electronics and Signal treatment.
RESEARCH SUPERVISOR
Dr Laurence MECHIN, CNRS research director and Pr Stéphane FLAMENT, Full professor at ENSICAEN
Email: Laurence.mechin@cnrs.fr and stephane.flament@ensicaen.fr
Research Group website (Url): Functional oxide group – Electronics team https://www.greyc.fr/en/equipes/electronics/
RESEARCH GROUP DESCRIPTION
The CNRS-GREYC laboratory has a staff of around 160 and carries out fundamental, methodological and applied research in the field of digital sciences. GREYC is recognised for its original contributions, its hardware and software achievements, its experimental validations and its multidisciplinary collaborations in the humanities and social sciences, as well as in the field of the interaction of computer science with mathematics and engineering sciences.
The Electronics team (around 30 people) works on various research activities relating to advanced electronic components and high-sensitivity sensors. The PhD student will be part of the Functional Oxide group within the CNRS-GREYC Electronics team (5 permanent researchers, 1 clean room engineer, 1 electronics engineer, 2 post-docs, 4 PhD students). In addition to Neuronanotech, the functional oxide group is currently involved in 2 regional projects, 2 French national projects and 1 international cooperation project. It was recently involved in the FET OPEN Byaxon project (www.byaxon-project.eu).
APPLICANT’S REQUIREMENTS
The candidate must have a background in electrical engineering and/or applied physics. Specific knowledge in magnetism, instrumentation or materials science will be appreciated.
Experience or competences as an experimentalist are expected.
The candidate should have an independent and efficient working attitude. They will participate in the communication of the results and must therefore have a good level of English.
ADDITIONAL PhD APPLICATION AND RECRUITMENT STEPS
The CNRS-GREYC laboratory is protected by a restrictive access regime (ZRR), which means that government-level authorisation is required for all applicants. This procedure will be initiated within our internal services during the recruitment process. A copy of passport/Id card and most recent grades will be required.
ELIGIBILITY CONDITIONS:
- Mobility requirements: candidates not have resided or carried out their main activity (work, studies, etc.) in France for more than 12 months in the 36 months immediately before the recruitment date.
- Research experience: must be doctoral candidates, i.e. not already in possession of a doctoral degree at the date of recruitment.
- Candidates must enrol in a doctoral programme in the relevant EU Member State/Associated Country.