MaProMoDe · Magnetic Properties of Molecular Deposition:low-temperature MFM and nanocalorimetry of sub-monolayers of magnetic molecules

Magnetic Properties of Molecular Deposition: low-temperature MFM and nanocalorimetry of sub-monolayers of magnetic molecules

As described in Annex 1, the ultimate goal of the project is to detect the magnetic signal from aggregates of magnetic molecules, deposited on a substrate by chemical methods and dip-pen nanolithography (work-package, WP 2). These molecules have potential applications in quantum information processing and magnetic microrefrigeration, as determined from "bulk" studies (WP 1). Our initial plan was to use a magnetic force microscope (MFM), working in the (2.8 - 300) K temperature range and in applied magnetic fields (WP 3). In addition, we were planning to use highly-sensitive sub-1 K calorimeters, whose fabrication by micro- and nanolithography were prospected as an objective of the proposal (WP 4). During the course of the whole two years, Dr. G. Lorusso has worked on the physical characterization at very low temperatures of selected molecule-based magnetic refrigerants in their bulk form (WP 1). She has acquired expertise on the determination of the magnetocaloric properties by means of magnetization and specific heat measurements. Her work resulted in ten publications, in top leading journals, e.g., "A dense metal-organic framework for enhanced magnetic refrigeration" by G. Lorusso et al., Adv. Mater. 25, 4653 (2013). In parallel, Dr. Lorusso has been introduced to AFM/MFM - a demanding technique, especially if experiments have to be carried out at liquid helium temperature (WP 3). Our team has successfully deposited a known molecular refrigerant, i.e., gadolinium acetate tetrahydrate, a molecular material characterized by a simple dinuclear core, onto silicon substrate by DPN (WP 2). Dr. Lorusso has led the subsequent quantitative MFM study. Our goal was to demonstrate that the grafted molecular refrigerants hold their functionality after the deposition, as a mandatory step for obtaining cooling microchips based on silicon (the ideal material for manufacturing the devices), capable of exploiting the features of such materials. This work has been published in: "Surface-confined molecular coolers for cryogenics" by G. Lorusso et al., Adv. Mat. 25, 2984 (2013), and was highlighted in the journal front cover and featured by the University of Zaragoza in a press release, by regional and national media, e.g., Aragón Universidad, Aragón Investiga, europapress.es, SINC, lainformacion.com, Heraldo de Aragón, etc., and by the European Institute of Molecular Magnetism. Dr. Lorusso has presented her results, as oral contributions, in different local and international meetings, that are, among others: the Fifth European School on Molecular Nanoscience (ESMolNa), in Cuenca, November, 2012; the Fourth European Conference on Molecular Magnetism (ECMM), in Karlsruhe, October 2013; the International Conference on Nanoscale Magnetism (ICNM), in Istanbul, September 2013. Finally, Dr. Lorusso has been collaborating in the development of Si-based highly-sensitive thermal sensors (WP 4), which will be the basis of future on-chip micro-refrigerators. We explored the limits of reducing the size of refrigerators down to the smallest scale, progressing towards innovative niche applications. Sub-kelvin microrefrigerators will significantly out-perform the current state-of-the-art NIS-based refrigerators. As there is a strong market driver to reduce bulk, weight and cost associated with the conventional refrigeration mechanisms, the molecule-based microrefrigerators are therefore industrially in-demand.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз