Abstract
The spontaneous polarization Ps of single‐domain orthorhombic KNbO3 has been measured with the Camlibel pulse method. A new value of Ps=0.41±0.02 C/m2, which is about 30% larger than the result obtained in hysteresis measurements, has been observed. The temperature dependence of the pyroelectric coeffficient has been measured using a direct method. The temperature dependence of the spontaneous polarization calculated from these measurements is compared with the results of a Devonshire free‐energy expansion.