Directional solidification of the eutectic LiF–LiYF4 using Bridgman and micro-pulling down techniques: Microstructural study and some properties

Abstract

The eutectic LiF−LiYF 4 has been solidified by Bridgman and micro-pulling down (mPD) at pulling rates from 4 to 300 mm/h. The microstructure changes from a coupled, interpenetrated-like one to macrofaceted colonies composed of an approximately triangular arrangement of LiF fibers inside the LiYF 4 matrix as the pulling rate increases. The cross-over pulling rate is around 3 times larger for the mPD method, corresponding to its larger solidification gradient. The crystallographic growth direction of the matrix phase was found using EBSD. Effective medium estimations of the THz permittivity of the composite predict around the interphase phonon-polariton resonance (wavelength around 17.5 µm) a small permittivity hyperbolic behavior specific of the ordered composite that is tolerant to different relative orientations. Water etching of polished crosssections constitutes a very simple procedure to generate surface micro-holes of predefined size in the LiYF 4 matrix.

Absorption effects on the Mie plasmon-polariton modes in two-dimensional plasmonic photonic crystals

“…Furthermore, in the present work we show the robustness of dipolar and quadrupolar Mie resonances to losses effects inherent to metallic inclusions. Present results may be useful for a complete understanding of a recent report, which show that plasmonic photonic band gaps (PBGs) are robust to disorder [36], making these systems very suitable to realize PBG media by bottom-up fabrication methods [37,38].…”

“…Also, we have found that Q sca resonances stemming from dipolar (Q 1 ) and quadrupolar (Q 2 ) contributions are robust to relatively strong absorption effects, implying that the design of those systems are not restricted to the use of low dissipative materials. On the other hand, due to the robustness to disorder of plasmonic gaps these systems are very suitable to design plasmonic PC-based absorbing platforms by using inexpensive bottom-up fabrication methods [37,38]. …”

A novel LiCl–BaCl2:Eu2+ eutectic scintillator for thermal neutron detection

“…The reduction of the production cost is based on exploiting advantages of the eutectic structure, i.e. faster synthesis process at the growth speed of mm/min as compared to mm/h of single crystals, and the ability to control the microstructure and dimensionality (λ) by tuning the solidification speed (v) thus satisfying the equation of vλ 2 ¼constant [2]. So far, several methods were successfully used for fabrication of eutectic scintillators, including the micro-pulling down, the Bridgman, and the Czochralski methods [2,3].…”

“…faster synthesis process at the growth speed of mm/min as compared to mm/h of single crystals, and the ability to control the microstructure and dimensionality (λ) by tuning the solidification speed (v) thus satisfying the equation of vλ 2 ¼constant [2]. So far, several methods were successfully used for fabrication of eutectic scintillators, including the micro-pulling down, the Bridgman, and the Czochralski methods [2,3]. The eutectic is formed by two immiscible phases from a completely miscible melt, and its typical microstructure is represented by a periodic arrangement of lamellar and rod-like phases [4][5][6].…”

Solidification of NaCl–LiF– $$\hbox {CaF}_{2}$$ CaF 2 ternary composites

“…metals, magnetic materials, semiconductors...), providing that they have an eutectic point in their phase diagram. The fabrication of metamaterial microstructures with a rich variety of shapes and configurations is then possible [22,[27][28][29][30][31][32][33]. Regular coupled growth of binary eutectics result in fibrous or lamellar arrangements [25,29,34].…”