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This work reports a novel bifunctional nanocomposite made of infrared-emitting nanophosphors and superparamagnetic nanoparticles, which simultaneously provides heating and temperature sensing at the nanoscale level. Highly luminescent Y3Al5O12:Nd3+ nanophosphors were synthesised by using a sol–gel route and were subsequently mixed with superparamagnetic nanoparticles producing a core–shell structure, which displayed superparamagnetic and fluorescent properties in the same nanostructured system. As a result, this bifunctional nanocomposite showed two essential characteristics: (i) it increased in temperature up to 57 °C upon exposure to an alternating magnetic field of sufficient strength and frequency, and (ii) its temperature could be optically sensed by monitoring the infrared luminescence emitted from the YAG:Nd nanophosphor. Our experiments revealed that the YAG:Nd/Fe3O4@SiO2 nanocomposite possesses excellent luminescence and superparamagnetic properties; both physical properties are driven in a non-contact manner making it appropriate for sensing local heating and temperature of cells, and also suitable to be used in medical treatments with minimal invasiveness.

New red luminescent powders of La(1-x)Pr(x)Sr2AlO5 (x = 0.01 at.) were prepared by the combustion synthesis method. Microstructural properties were characterized by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The La(1-x)Pr(x)Sr2AlO5 X-ray diffraction pattern revealed a tetragonal phase. Morphology of the grains showed nanobars with sizes of approximately 550 nm in length. Photoluminescence, cathodoluminescence and diffuse reflectance were analyzed in detail. Photoluminescence revealed two narrow emission peaks located at lambda(em1) = 497 nm (green) and lambda(em2) = 620 nm and a single maximum excitation peak of lambda(ex) = 287 nm. The cathodoluminescence spectrum confirmed the peaks detected by photoluminescence analysis. The absorbance spectrum showed broad absorption with a maximum around lambda = 280 nm, which agrees with the maximum excitation peak detected by photoluminescence.

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