Field cooled and zero field cooled 207Pb NMR of the relaxor ferroelectric PMN

A 2.8 kV/cm electric field has been applied parallel to the external magnetic field along the [111] direction of a PMN single crystal and the 207Pb NMR spectra were measured at 9.1 T. Whereas the zero field cooled (ZFC) spectrum exhibits a Gaussian-like line shape, the FC spectrum clearly shows a two peak structure. One of the two peaks coincides with the ZFC spectrum. The other peak is shifted by about 100 kHz towards lower frequencies with respect to the ZFC peak and seems to be characteristic for the ferroelectric state. The ferroelectric shift agrees with the predictions of the spherical random bond–random field model. [Copyright &y& Elsevier]