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Thermal depolarization has been measured for crystals of KCl doped with SrCG. Suoh crystals annealed at 623 K for one hour and then quenched display one major relaxation peak characterized by an activation energy of 0.74 eV. But if the annealing time is extended to 15 h a t the same temperature two relaxation processes with activation energies of 0.68 and 0.74 eV are observed. The dependence of the dipole relaxation spectrum on annmling time a t 250 K is measured. It is concluded that the relaxation process with E = = 0.68 eV is associated with Ma+-cation vacancy complexes and that with E = 0.74 eV is associated with dimers formed from two of these complexes.Die thermische Depolarisation wird fur SrCI,-dotierte KC1-Kristalle gemessen. Solche bei 623 K eine. Stunde getemperte und d a m abgeschreckte Kristalle zeigen ein Haupt-Relaxationsmaximum, das durch eine Aktivierungsenergie von 0,74 eV charakterisiert ist.Wenn jedoch die Temperungsdauer auf 15 Stunden bei der gleichen Temperatur ausgedehnt wird, werden zwei Relaxaiiansprozesse mit den Aktivierungsenergien 0,68 und 0,74 eV beobachtet. Die Abhiingigkeit des Dipolrelaxationsspektrums von der Temperungsdauer bei 250 K wird gemeseen. Es wird geschlossen, daI3 der RelaxationsprozeD mit E = 0,68 eV mit Me+-Kationenleerstellen-Komplexen und der mit E = 0,74 eV mit Dimeren verknupft ist, die &us zwei dieser Komplexe gebildet sind.

The presence of CrO42− ions incorporated substitutionally in single crystals of NH4ClO4 grown from saturated solutions containing 0.1 mol% or 1 mol% CrO42− ion has been demonstrated by measurements of optical absorption, Raman scattering, dielectric loss, and ionic thermoconductivity. The three latter experiments also show the presence of dipoles associated with the CrO42− ions. The dc conductivity of NH4ClO4 crystals is enhanced by doping with CrO42− so that charge transport by defects introduced by the CrO42− ions is inferred. The implications of this finding with respect to mechanisms of charge transport in ammonium perchlorate are discussed.