Sin categoría – Multifunctional Magnetic Molecular Materials https://m4.unizar.es M4 Mon, 30 Nov 2020 14:04:15 +0000 en-US hourly 1 https://wordpress.org/?v=5.5.18 Thermometry at the nanoscale https://m4.unizar.es/thermometry-at-the-nanoscale/ Mon, 30 Nov 2020 14:04:15 +0000 https://m4.unizar.es/?p=4173 In response to the need of real-time non-contact thermometry with submicron resolution and high sensitivity readout in Nanotechnology in general and NanoBioMedicine in particular, the group has developed a new technology based on the use of luminescence nanosensors and a fluorescence detection instrument. The nanoprobes consist of ad hoc designed copolymers bearing lanthanide luminescence complexes. The detection instrument consist of a fluorescence microscope coupled to a beam splitter, a CMOS camera and a software that transform the emission of the nanosensors into temperature images in real time. This system is able to map the temperature in the interior of cells and the local temperature of nanoheaters coated with the designed copolymers. The instrument is actually used in studies of mitochondria activity, and local hyperthermia therapy. Moreover, the group has also developed an alternative temperature scanning method using similar molecular temperature sensors and a double optical fibber probe to determine the temperature on surfaces (i.e. chips). The molecular thermometers are spread on the surface as paint or as self-assembled monolayer.

]]> Calorimetry goes nano https://m4.unizar.es/calorimetry-goes-nano/ Sun, 25 Oct 2020 22:10:40 +0000 https://m4.unizar.es/?p=3985 Thermodynamic measurements give a great deal of information on fundamental properties, providing direct and quantifiable insight into, e.g., densities of state and phase transitions. Many interesting materials are obtained in the form of sub-microgram single-crystals, thin films or even grafted monolayers. The mass of these samples is extremely small and so is their heat capacity. Therefore, this makes conventional calorimeters unsuitable.

Using micromachining technology, we fabricate and develop different types of membrane-based nanocalorimeters. They can be operated in either modulation (AC) calorimetry or relaxation calorimetry, over a broad range of temperatures and applied magnetic fields. We employ our devices for challenging studies on magnetic systems, including spin-crossover compounds and molecules for applications in quantum information and magnetic refrigeration on a chip.

Top: Photograph of a calorimeter based on a Si (left) or Si3N4 (right) membrane with a ca. 100 nanogram single-crystal of [FexM1-x(btr)2(NCS)2]·H2O (highlighted by the arrow). Sample is a courtesy of Kamel Boukheddaden.

 

Top left: Temperature response of the calorimeter to a heat pulse. Blue line is the fit to an exponential relaxation. Top right: Experimental zero-field heat capacity. Data are collected with a homemade calorimeter, based on a Si3N4 membrane, for a ca. 100 nanogram single-crystal of [FexM1-x(btr)2(NCS)2]·H2O. Sample is a courtesy of Kamel Boukheddaden.

 

Top left: Photograph of a calorimeter based on a Si3N4 membrane with a ca. 5 nanogram single-crystal flake of FePS3 (highlighted by dotted lines). Top right: Its experimental zero-field AC heat capacity that shows antiferromagnetic ordering (see the peak heat capacity in the inset). Sample is a courtesy of Samuel Mañas.

 

The team

Giulia Lorusso, Juan José Morales, Michel Castro, and Marco Evangelisti.

]]>