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Synthesis and physico-chemical characterization

Bastien Loret (PhD student), Anaëlle Legros (PhD student), Anne Forget, Dorothée Colson

Part of the group's activity is focused on the synthesis and the physicochemical study of solid state materials as single crystals or ceramics, mostly oxides. We dedicate our research to materials with remarkable properties as high-temperature superconductors (cuprates and pnictides), multiferroic oxides and iridates.

Different routes of preparation are used depending on the type of desired sample. The solid state reaction technique of finely ground oxides or carbonates at high temperature (800 °C – 1500 °C) allows the synthesis of polycrystalline samples. Sintering involves annealing these samples previously compacted, below their melting point, thereby improving their density as a function of their degree of compaction.

The synthesis of single crystals is performed using a flux growth technique. It allows crystallization of such oxides from a liquid phase, the temperature is chosen below the melting point or below of the decomposition temperature of the material.

The syntheses are performed in air, in a controlled atmosphere or in sealed quartz ampoules under vacuum (for example for mercury cuprates or iron pnictides).

The study by X-rays diffraction of synthesized materials will then allow to verify the crystalline organization, the possible impurity phases and optimizing of the synthesis parameters as temperature, duration, cooling rate...

The physical properties (magnetic and transport) of samples are measured by physicists in the group. We also collaborate with many external laboratories.

This strong interaction between chemists and physicists is an asset for samples optimization, it enables us to develop homogeneous materials with a high purity degree.

Our main equipments:

  • basic tools for samples synthesis
  • 2 precision weighing balances
  • 2 presses
  • 2 temperature chambers
  • 1 ultrasonic tank
  • two glove boxes
  • dessicator cabinets
  • several conventional tube furnaces (Tmax = 1200 °C)
  • 4 furnaces under controlled atmosphere (Tmax = 1200 °C and 1500 °C )
  • 3 muffle furnaces (Tmax = 1200 °C and 1600 °C)
  • 1 autoclave under molecular oxygen (Tmax = 400 ° C, High Pressure max = 200 bars)
  • 1 saw with horizontal wire, one circular diamond saw
  • 2 binoculars
  • X-rays diffractometer for powders analysis
  • thermal analyzer (DSC-TGA),
  • magnetometry (Squid, VSM)
  • transport measurement system (PPMS)
 

 

 

Maj : 09/11/2016 (2643)

Voir aussi
Superconductivity is a fascinating state of matter in which electric current flows without dissipation of energy. For thirty years, the search for high-temperature superconductors focused on cuprates, however, the origin of the pairing mechanism is not yet clear because of the high structural and ... Lire la suite »
Regarding multiferroic oxides, the group has developed very resistive crystals that have enabled to demonstrate, for the first time, the multiferroic character at room temperature of the BiFeO3 compound and determine a very high electric polarization value (P> 100 μC / cm 2 >> 25 μC ... Lire la suite »
The iridates (eg Sr2IrO4, Sr3Ir2O7 ...) have recently attracted the attention of the scientific community due to the presence of a strong spin-orbit coupling and strong electronic interactions that give rise to original physical properties as the high Tc superconductivity or the state of ... Lire la suite »
 

 

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