Abstract:© Versita Sp. z o.o. A novel composite superionic system, [Ag 2 HgI 4 :0.2AgI]:xCuI, (x = 0.2, 0.4, 0.6 mol. wt.%), was prepared and [Ag 2 HgI 4 :0.2AgI] mixed system was used as the host. Electrical conductivity was measured to study the transition behavior at frequencies of 100 Hz, 120 Hz, 1 kHz, and 10 kHz in the temperature range 90° -170°C by a Gen Rad 1659 RLC Digibridge. Sharp increase in conductivity was observed for β-α phase transitions. As a result of increase in the dopant-to-host ratio, the conductivity of the system exhibited Arrhenius (thermally activated)-type behavior. X-ray powder diffraction, differential scanning calorimetry (DSC), differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) studies confirmed the doping effect on the transition in the host, the phase transition temperature increased with an increase in the dopant concentration. Activation energies for the system in eV both for the pretransition and post-transition phase transformations are reported.

Experimental MaterialSilver iodide (AgI) and mercury [I] iodide (HgI 2 ) were of CDH Analar grade, cuprous iodide (CuI) was obtained from S.D. Fine-Chem (India), and potassium sulfate (K 2 SO 4 ) was obtained from Qualigens with stated purity of 98%, 99%, 99%, and 99% each, respectively. Preparation and characterization of pure and doped samples Preparation of host [Cu 2 HgI 4 :0.2AgI] compositeThe samples were prepared by precipitation using previously described techniques as well as by solid-state reaction [15,16]. Cu 2 HgI 4 was prepared by solid-state reactions between CuI and HgI 2 [5]. 2CuI s ð Þ þ HgI 2 s ð Þ ! Cu 2 HgI 4 s ð Þ

Newcomposite superionic systems, [CdHgI 4 : 0.2AgI] : 0.xKI and [CdHgI 4 : 0.2AgI] : 0.xK 2 SO 4 (x ¼ 0.2, 0.4, 0.6 mol. wt%), were prepared, using [CdHgI 4 : 0.2AgI] mixed composite system as the host. Electrical conductivity was measured to study the transition behavior at frequencies of 100 Hz, 120 Hz, 1 kHz, and 10 kHz in the temperature range from 150 C to 250 C using a GENRAD 1659 RLC Digibridge. A sharp increase in conductivity was observed during ! phase transition. Upon increasing the dopant-to-host ratio, the conductivity of the superionic systems exhibited Arrhenius (thermally activated)-type behavior. Differential thermal analysis, differential scanning calorimetry, thermogravimetric analysis, and X-ray powder diffraction were performed to confirm the doping effect and transition in the host. The phase transition temperature increased with an increase in the dopant concentration. Activation energies in eV for pre-and post-transition phase behavior are reported.

A novel composite superionic system, [Cu 2 HgI 4 : 0⋅xAgI], (x = 0⋅2, 0⋅4, 0⋅6 mol wt.%), was prepared. A [Cu 2 HgI 4 ] system was used as the host. Electrical conductivity was measured to study the transition behaviour at frequencies of 100 Hz, 120 Hz, 1 kHz and 10 kHz in the temperature range 90-170°C using a Gen Rad 1659 RLC Digibridge. Conductivity increased sharply during the β-α phase transition. Upon increasing the dopant-to-host ratio, the conductivity of the superionic system exhibited Arrhenius (thermally activated)-type behaviour. DTA, DTG, TGA and X-ray powder diffraction were performed to confirm doping effect and transition in the host. The phase transition temperature increased with an increase in the dopant concentration. Activation energies in eV for pre-and post-transition phase behaviour are also reported. Due to an interaction between [Cu 2 HgI 4 ] and AgI, the addition of AgI to [Cu 2 HgI 4 ] shifted the phase transition of the host [Cu 2 HgI 4 ].

No abstract