KLaF4:Nd3+ doped transparent glass-ceramics processed by spark plasma sintering

[EN] Transparent oxyfluoride glass-ceramics (GCs) containing KLaF4 nanocrystals (NCs) doped with Nd3+ were prepared by Spark Plasma Sintering (SPS). Glass powder pellets were sintered under a vacuum atmosphere, optimizing the processing parameters such as particle size, pressure, temperature, and holding time to obtain full densification. Transparency decreased when decreasing the particle size due to higher carbon contamination from the die. The alpha-KLaF4 crystalline phase was identified by X-ray diffraction (XRD) and its average crystal size was 10-20 nm. High-resolution transmission electron microscopy (HR-TEM) confirmed the presence of KLaF4 nanocrystals with incorporated Nd3+ ions. Low-temperature site-selective emission and excitation spectra of Nd3+ ions confirmed that alpha-KLaF(4 )was the predominant polymorph, although a minor presence of beta- KLaF4 was also demonstrated.This work was supported by MINECO under Projects MAT2017-87035-C2-1-P/-2-P (AEI/FEDER, UE) , PID2020-115419GB-C-21/C-22 and Basque Country Government PIBA2018-24. AAC also thanks the scholarships of the Federal Agency for the Support and Improvement of Higher Education (CAPES) , contract #99999.002598/2015-09. This paper is part of the dissemination activities of project FunGlass. This project has received funding from the European Unions Horizon 2020 research and innovation program under grant agreement No 739566