Structure and dielectric response of $(1-x)$NaNO$_{2}$ + $x$BaTiO$_{3}$ composites at $x$ = 0.05 and 0.1

The $(1-x)$NaNO$_{2}$ + $x$BaTiO$_{3}$ composites of two compositions ($x$ = 0.05 and 0.1) have been studied by powder neutron diffraction and broadband dielectric spectroscopy (frequency region 10$^{-1}$ – 10$^7$ Hz). The temperature dependences of the ferroelectric order parameter of NaNO$_2$ in the composites and pure NaNO$_2$ have been measured. The frequency dependences of the real and imaginary parts of the permittivities of the composites and pure NaNO$_2$ have been analyzed in the temperature range 25–187$^\circ$C. The anomaly of the dielectric response observed at $T\sim$ 147$^\circ$C is assumed to be related to the processes of accumulation and “resolution” of charges at the BaTiO$_3$ particle boundaries.