Experimental Evaluation of the Acceptor‐States Compensation in Positive‐Temperature‐Coefficient‐Type Barium Titanate

Experimental evidence shows that the acceptor‐state levels in Sb‐doped positive‐temperature‐coefficient‐type BaTiO 3 are compensated up to a critical acceptor‐state density. Using the slope of the natural logarithm of the resistivity with respect to 1/ T , instead of maximum resistivity as a measure for the acceptor‐state density, it is possible to estimate this critical value. The value obtained (4.2 × 10 17 m −2 ) is believed to be the first reported estimate based on experimental data. It is in good agreement with the estimate of 6 × 10 17 m −2 (first reported by Jonker) obtained from the spontaneous polarization of BaTiO 3 . This shows that the ferroelectric behavior of BaTiO 3 is indeed a feasible explanation for the low resistivity below the Curie point, as proposed by Jonker.