INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
The temperature dependence of the hyperfine interaction in the cubic phase of BaTi(1-x)Hf(x)O(3)
A. LÓPEZ GARCÍA; R. E. ALONSO
Buenos Aires, Argentina
Congreso; Ismanam 2008; 2008
Recently, a crossover from classical to relaxor ferroelectrics, for compositions x = 0.3 and 0.4 in BaTi(x)Hf(1-x)O(3) been observed.  In these compounds, the temperature dependence of the real and imaginary part of the permitivity measured at different frequencies show that the transition temperature shifts. Instead, the dielectric coefficient is relatively sharp at low Hf concentration (x = 0.05, 0.1 and 0.2) and the value of Tm (the transition temperature from paraelectric to ferrolectric phase) is frequency independent. In this contribution the temperature dependence of the hyperfine quadrupole interaction measured with Perturbed Angular Correlations (PAC) spectroscopy in the cubic phase of the family of compounds BaTi(1-x)Hf(x)O(3) for 0<x<1 was used to study the nanoestructure of these compounds. In order to explain these results a model consisted of random distributed polarized oxygen vacancies and different degree of covalency in Ti-O and Hf-O bonds is proposed to explain the PAC results.