V. S. Amaral

A luminescent molecular thermometer for long-term absolute temperature measurements at the nanoscale

Temperature is a fundamental thermodynamic variable, the measurement of which is crucial in countless scientific investigations and technological developments, accounting at present for 75%–80% of the sensor market throughout the world.[1] Traditional liquid-filled and bimetallic thermometers, thermocouples, pyrometers, and thermistors are generally not suitable for temperature measurements at scales below 10 μm. This intrinsic limitation has encouraged the development of new non-contact accurate thermometers with micrometric and nanometric precision, a challenging research topic increasingly hankered for [1–2].

Silica coated magnetite particles for magnetic removal of Hg2+ from water

The magnetic removal of Hg(2+) from water has been assessed using silica coated magnetite particles. The magnetite particles were first prepared by hydrolysis of FeSO(4) and their surfaces were modified with amorphous silica shells that were then functionalized with organic moieties containing terminal dithiocarbamate groups. Under the experimental conditions used, the materials reported here displayed high efficiency for Hg(2+) uptake (74%) even at contaminant levels as low as 50 μg l(-1). Therefore these eco-nanomagnets show great potential for the removal of heavy metal ions of polluted water, via magnetic separation.

Lanthanide-based luminescent molecular thermometers

Non-invasive accurate thermometers with high spatial resolution and operating at sub-micron scales, where the conventional methods are ineffective, are currently a very active field of research strongly stimulated in the last couple of years by the challenging demands of nanotechnology and biomedicine. This perspective offers a general overview of recent examples of accurate luminescent thermometers working at micrometric and nanometric scales, particularly those involving advanced Ln3+-based functional organic–inorganic hybrid materials.

The effect of magnetic irreversibility on estimating the magnetocaloric effect from magnetization measurements

We found that the anomalous magnetic entropy change peak obtained from magnetization measurements in some first-order magnetic phase transition materials may result from the usual data analysis procedure, which does not take into account magnetic irreversibility or mixed-phase regime. The deviations produced are comparable to anomalous effects discussed in the literature and may even exceed the theoretical limit. Our results show that this anomalous magnetic entropy change peak should not necessarily be interpreted as a consequence of the particular physics of the studied system. This also explains its absence in specific heat measurements.

Relevance of magnetic moment distribution and scaling law methods to study the magnetic behavior of antiferromagnetic nanoparticles : Application to ferritin

The analysis of magnetization of antiferromagnetic nanoparticles is not straightforward due to the presence of a linear component,

New phase transition in the Pr1-xCaxMnO3 system: evidence for electrical polarization in charge ordered manganites.

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Efficient sorbents based on magnetite coated with siliceous hybrid shells for removal of mercury ions

superimposed on the saturation and the inexistence of a simple relation between size and magnetic moment

On the Curie temperature dependency of the magnetocaloric effect

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A mean-field scaling method for first- and second-order phase transition ferromagnets and its application in magnetocaloric studies

. We present a method, based on scaling laws, to determine the variation of

Temperature dependence of antiferromagnetic susceptibility in ferritin

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