Impurity induced effect for the paraelectric to ferroelectric transition in a NaNO2-KNO3 mixture observed by Na-23 NMR

摘要

The spin-lattice relaxation rate for the Na-23 NMR central transition in NaNO2(1-x)KNO3(x) (X = 0, 0.2) has been investigated in the temperature range of 298-451 K. In the mixture NaNO2(0.8)KNO3(0.2), a non-exponential behavior of the magnetization recovery and the narrowing of the linewidth are observed at 415 K. This anomaly appears to be attributed to the phase transition of KNO3 in the mixture, as shown in the result of differential scanning calorimetry (DSC). The transition temperature from the para- to ferroelectric phase in the mixture decreases slightly compared with that in the pure NaNO2. This can be explained in terms of the change of spontaneous polarization. (C) 2001 Published by Elsevier Science Ltd. References: 16