A Good Place for Materials Scientists and Mineralogists to prepare their EM Samples

Partner lab at IMPMC, Paris, well received by users

August 07, 2015

In June 2014, the Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC) of the Université Pierre et Marie Curie in Paris became a Leica reference lab for EM Sample Preparation with equipment like the Leica EM TXP target surfacing systems and the Leica EM TIC 3X ion beam milling system. In the interview, Imène Estève, engineer at the Centre National de Recherches Scientifiques (CNRS) and head of the SEM-FIB national facility, in charge of running the lab, tells us about how this cooperation has developed.

The reference lab has been running for about a year now – how well has it been received?

Imène Estève: Very well, indeed. The instruments enable us to prepare a wide range of samples, which can be very different in shape or structure, from diamond crystals to specimen in suspension to heat sensitive resins which request cryo preparation. We see that the free access to the instruments and their ease of use have made them very popular within our lab. Also our electron microscopy platform receives requests for EM sample preparation from nearby institutes.

What types of samples have you been able to process since your lab has been equipped with the Leica EM TXP and the Leica EM TIC 3X?

Imène Estève: To date, we have prepared various materials. We have processed different alloys made of copper, titanium or aluminum, as well as rocks such as meteorites or argillite, minerals, for example diamonds, polymers and catalyzers. Materials can come in different shapes, in bars, powders, thin foils, stones, or cladding – the only aspect they all have in common is that they require to be handled with care, for example at cryogenic or anoxic state.

Fig. 1: Argilite, pre-prepared with Leica EM TXP and ion beam polished with Leica EM TIC 3X, EHT = 15.00 kV, WD = 7.0 mm, signal A = BSD, width = 673.5 µm, mag = 448 x.
Fig. 2: Imène Estève, engineer at the Centre National de Recherches Scientifiques (CNRS) and head of the SEM-FIB national facility

What are the main benefits that you get from using Leica EM sample preparation systems in your workflow?

Imène Estève: The main advantage is that we are able to prepare and polish a large surface, free of any cracks from hardening or mechanical artefacts in the range of a couple of millimeters, where with the focused ion beam (FIB), for instance, polishing of only a couple of microns could be achieved.

This type of sample preparation reduces the number of steps required prior to sample observation and analysis and is remarkably versatile at the same time. We can use the Leica EM TXP and EM TIC 3X on "hard / soft" interfaces, fragile, porous, and textured materials as well as composites which are now eligible to micro analysis in the scanning electron microscope, with focused ion beam milling, microprobes, or nanoSIMS.

Wherever imaging techniques in electron microscopy perform well on specific targets, it becomes enormously important if the sample is homogenous and characteristic. This observation matrix allows putting the analyzed object into context, whether geological, chronological, environmental, or else, to recreate millimetric gradients and realize more statistical analysis.

Have you made new discoveries in application terms thanks to the use of Leica instruments?

Imène Estève: We were able to accelerate some focused ion beam applications thanks to a pre-preparation of the sample with the Leica EM TIC 3X. This applies to diamonds and rocks, especially for 3D reconstructions. Furthermore, we are currently introducing a new sample preparation protocol for diamond anvil cells which combines laser cutting and ion beam polishing with the Leica EM TIC 3X and focused ion beam.

What do you particularly appreciate in the concept of this lab?

Imène Estève: The partnership is a privilege for both our lab and Leica Microsystems, because our exchange enables both parties to benefit by developing their expertise and know-how. The opportunity to test the most recent instruments in the workflow allows us to better evaluate the match between our needs and the performance of the instruments very thoroughly.

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