THERMALLY-INDUCED DEPOLARIZATION CURRENT SPECTRA OF NACL NI2+ CRYSTALS

The technique of thermally stimulated depolarization currents was exploited to search dipolar defects in NaCl crystals doped with divalent nickel in a wide concentration range. The results were critically compared with those typical of other impurities. It has been shown that the main features of the detected polarizations are qualitatively similar to those characteristic Of alkali halides doped with divalent cations. The differences observed in some instances can be understood in terms of different mobility and/or stability of the elementary defects related with the impurities.