Negative-resistance behavior of bulk Ag 2 O–TeO 2 –V 2 O 5 oxide glasses

Abstract

The bulk 3-component xAg₂O–40TeO₂–(60 − x)V₂O₅ oxide glasses with different silver oxide contents of x = 0, 10, 20, 30, 40 and 50 mol% were prepared using the standard press-melt quenching method. The effect of the high DC electric field on the DC conductivity of the mentioned glasses was investigated using the gap-type electrode configuration. At the regime of low DC electric fields, the conduction of these samples was ohmic, whereas at high electric fields regime, present bulk samples show nonlinear behavior (i.e., non-ohmic conduction). The current–voltage characteristics show increasing deviation from Ohm's law with increasing current density, implying the non-ohmic behavior in close coincidence with Poole–Frenkel effect (PFE) which occurs at electrical fields nearly above 10⁴ (V/cm); so, samples show the switching phenomena at a threshold voltage (V_th) from resistive state to conductive state. Based upon PFE, the lowering factor of potential barrier (β_PF) was determined for the understudied samples. Also, results show that generally the threshold voltage in which switching phenomenon occurs increases by increasing the electrode distance and decreases by increasing the sample temperature, but V_th shows two distinct regions of 0 ≤ x ≤ 20 and 20 < x ≤ 50, in which the highest value of V_th is devoted to the case of x = 20 mol% with respect to other glasses; this result implies the structural change and then probable formation of crystallites in the amorphous matrix to be hard for the mentioned case, which is in good agreement with the previously reported mechanical aspects.

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