INVESTIGADORES
ALONSO Roberto Emilio
congresos y reuniones científicas
Título:
Analysis of the infrared active modes of BaHfO3
Autor/es:
R. E. ALONSO; P. DE LA PRESA; N. MASSA; A. LÓPEZ GARCÍA
Lugar:
Campinas, Brasil
Reunión:
Congreso; VII Workshop Anual de Usuarios del LNLS; 1996
Resumen:
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The
BaHfO3 is a compound belonging to ABO3 perovskite family
whose structure is reported as cubic over the whole temperature range, similar
to that of the BaTiO3 paraelectric phase. Meanwhile, the x-ray
diffraction spectroscopy (XRD) assign to this compound a cubic structure,
perturbed angular correlation spectroscopy (PAC) shows a dynamic effect around
the probes (Hf sites), measured from RT to 1100C. This last means that the mean
value of the principal component of the electric field gradient tensor at the
probes 181Ta(Hf) is non vanishing and fluctuating with time.
The
aim of this work is to give some light about this problem. In that way, we
measured this compound by far infrared spectroscopy (FIR) at 80 K. The spectra show
that although the main cubic perovskite bands are well defined, appear in them
weaker substructure that implies a lower effective space group. Our analysis of
the data by KK and LST generalized model indicate that it is possible to
explain these extra peaks with an orthorhombic distortion similar to that we
already found for SrHfO3.
