Post-doctorat Development of new magnetization probes for the pulsed magnetic fields (M/F)

Job Description

Missions

In magnetically-ordered quantum magnets, first- and second-order magnetic phase transitions are generally induced between states of different magnetic structures, leading sometimes to the presence of magnetization plateaus. In quantum paramagnets, a sudden magnetic polarization associated with a steplike variation of the magnetization can also be induced under magnetic fields at a first order transition, as observed at the metamagnetic transition of Ising-anisotropy heavy-fermion systems. In a few U-based materials, as UTe2 or URhGe, a metamagnetic transition is associated with the development of field-induced superconductivity at low temperature, whose mechanism was proposed to be triplet. In these systems, the critical magnetic fluctuations developing at the metamagnetic transition are suspected to drive the unconventional superconducting mechanism. A challenge is to understand the interplay between the magnetic and superconducting properties in these quantum materials.

Activity

This postdoc project will consist in the development of new magnetization probes for the pulsed magnetic fields generated at the LNCMI-Toulouse. Recent preliminary measurements have shown the feasibility of the project. With this new setup, magnetization experiments will be performed on the new superconductor UTe2 under different sets of extreme conditions, under magnetic fields up to 70 T combined with temperatures down to 1.4 K, magnetic fields up to 60 T combined with temperatures down to 100 mK, and magnetic fields higher than 90 T combined with temperatures down to 1.4 K. The scientific target will be to investigate the relationship between the magnetic properties and the appearance of unconventional superconductivity under intense magnetic fields, near a metamagnetic transition.

Your Profil

Skills

Within step 1, magnetization-probe prototypes of different geometries, based on the compensated coil technique, will be developed, tested and compared before choosing the best configuration for experiments in a 70-T magnet, at variable temperatures from 1.5 to 300 K. The first magnetization measurements will be performed on the superconductor UTe2, with the aim to extract the magnetic-field variation of the low-temperature Sommerfeld coefficient (from the temperature dependence of the magnetization via a thermodynamic relation), which is driven by quantum critical magnetic fluctuations, for magnetic fields of different directions. Within step 2, a magnetization probe will be tested in a new dilution fridge recently built by the Cryogenics team at the LNCMI. The scientific target will be then to characterize the hysteresis induced by the magnetic flux pinning by the superconducting vortices in the magnetization of UTe2 under magnetic fields up to 60 T combined with temperatures down to 100 mK. In parallel, the post-doctorant will be associated as co-local contact to studies of other quantum materials using his/her compensated-coil magnetization probe, in collaboration with LNCMI researchers or external visitors.

Your Work Environment

The Laboratoire National des Champs Magnétiques Intenses in Toulouse (LNCMI-T) is one of the few facilities worldwide delivering non-destructive pulsed magnetic fields up to more than 90 teslas. Such extremely high magnetic fields constitute a powerful tool for the study of condensed matter physics. In addition to the internal research performed by its staff, the LNCMI offers an access to his experiments under high magnetic field to external researchers, via the submission of scientific proposals evaluated by an international selection committee. The postdoctoral researcher will work in the scientific team 'Quantum conductors and magnets' of the LNCMI-T. He/she will collaborate with researchers and engineers at the LNCMI-T and with researchers from the CEA-Grenoble and Tohoku University in Japan. The postdoctoral research position is funded for ≥ 14 months by the grant NanoX n° ANR-17-EURE-0009 in the framework of the “Programme des Investissements d'Avenir. The net salary (after deduction of social security and income taxes) is between 2500 and 3500 € / month, depending on the work experience. The start date can be as soon as possible.

Compensation and benefits

Compensation

between 3041 euros and 4668 euros

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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