The Frequency Dependence of the Conductivity and Dielectric Relaxation of [(CH₂)₃(NH₃)₂]Cu(II)Cl₄

Abstract

The structural, dielectric and conductive properties of [(CH 2 ) 3 (NH 3 ) 2 ]Cu(II)Cl 4 have been studied. The material shows an order-disorder transition at T 1 = (333 ± 2) K and a ferroelectric phase transitions at T 2 = (434 ± 3) K. Results of differential thermal analysis, infrared spectroscopy, X-ray diffraction, AC conductivity and permittivity measurements are reported and discussed. The conductivity results are interpreted in terms of barrier hopping at low and intermediate temperatures, and band-type conduction at high temperatures. -PACS: 81.05.-t, 77.22.-d

On the Structural Phase Transition in a Perovskite-Type Diaminopropanetetrachlorocuprate(II) NH3(CH2)3NH3CuCl4 Crystal

“…This value is smaller than that expected in the case of an order-disorder transition with two equilibrium positions described by the well known formula ∆S = R ln 2 = 5.76 J/(mol K). The temperature of this transition is in agreement with the temperature presented in [8] although the shape of DSC anomaly presented in [8] is very broad and strange (not characteristic for a phase transition). The enthalpy and entropy for this transition are smaller in comparison to those observed in [8].…”

“…The temperature of this transition is in agreement with the temperature presented in [8] although the shape of DSC anomaly presented in [8] is very broad and strange (not characteristic for a phase transition). The enthalpy and entropy for this transition are smaller in comparison to those observed in [8]. We do not observe any traces of the phase transition at about 334 K in comparison to the observation in [8] where a large thermal anomaly was observed.…”

“…The enthalpy and entropy for this transition are smaller in comparison to those observed in [8]. We do not observe any traces of the phase transition at about 334 K in comparison to the observation in [8] where a large thermal anomaly was observed. From the DSC studies one can distinguish two phases, namely the phase I below 436 K and the phase II above 436 K.…”

“…Two structural phase transitions were found at 305 K and 337 K in [NH 3 (CH 2 ) 3 NH 3 ]MnCl 4 [6]. The [NH 3 (CH 2 ) 3 NH 3 ]CuCl 4 (abbreviated as DAPCCl) crystal is orthorhombic [7,8] and isomorphous with [NH 3 (CH 2 ) 3 NH 3 ]CdCl 4 at the room temperature phase [1]. Two successive phase transitions are proposed to appear at 334 K and 433 K [8] and the transition at 433 K is regarded as irreversible.…”

“…The [NH 3 (CH 2 ) 3 NH 3 ]CuCl 4 (abbreviated as DAPCCl) crystal is orthorhombic [7,8] and isomorphous with [NH 3 (CH 2 ) 3 NH 3 ]CdCl 4 at the room temperature phase [1]. Two successive phase transitions are proposed to appear at 334 K and 433 K [8] and the transition at 433 K is regarded as irreversible. The aim of our study is to grow the crystal, check and characterize the observed phase transitions in more detail and to study some physical properties of the single crystal.…”