Quadruple node of triple junctions of grain boundaries in a Eu2+-doped solid solution of the ions K plus , Rb plus , Cl- and Br-: an epifluorescence microscopy study using the doping ion as a fluorochrome
Por:
Cordero-Borboa, Adolfo Ernesto, Unda-Angeles, Rodrigo
Publicada:
1 abr 2022
Resumen:
Epifluorescence microscopy was used to unveil the geometry and relative
spatial orientation of an arrangement of crystal defects, consisting of
a quadruple node of triple junctions of grain boundaries, in a
Eu2+-doped solid solution of K+, Rb+, Cl- and Br-. The doping ion was
utilized as a fluorochrome. Microscopy images of different optical
cross-sections of the arrangement of crystal defects under study were
recorded and used to build an electronic three-dimensional
reconstruction of this arrangement. The geometry is that of an irregular
tristetrahedron, centred at the quadruple node, so that the
tristetrahedron legs, deviating from the lattice -zone axis directions,
lie along the triple junctions, whereas the tristetrahedron faces
collapse onto the grain boundaries. The deviation angles as well as the
angles defined by different triple junction pairs and different grain
boundary pairs were measured. The orientational deviation is larger than
that in a KI single crystal but lower than that in a solid solution of
K+, Cl- and Br-, meaning that the structural equilibrium depends on the
matrix lattice structural character. Uncompensated local nanostrains,
due to the ion substitution, are associated with the observed decrement
in structural stability, in relation to the KI case, whereas compensated
local nanostrains, provoked by the simultaneous substitution of cations
and anions, are argued to be responsible for the observed increment in
structural stability, in relation with the K(Cl, Br) case. The optical
characterization of the fluorochrome, the recording and processing of
the microscopy images, the building of the electronic 3D reconstruction,
the angular measure methodology and the geometrical modelling are all
carefully described.
Filiaciones:
Cordero-Borboa, Adolfo Ernesto:
Univ Nacl Autonoma Mexico, Inst Fis, AP 20-364, Mexico City 01000, DF, Mexico
Unda-Angeles, Rodrigo:
Univ Nacl Autonoma Mexico, Inst Fis, AP 20-364, Mexico City 01000, DF, Mexico
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