Conduction Phenomena in Thin Layers of Iron Oxide

Abstract

Results on studies of tunneling and conduction phenomena in thin metal-iron-oxide-metal sandwiches at helium temperature are described in this paper. Characteristic I-V curves have been studied for both dc and ac applied voltage signals. The main features of interest are a voltage breakdown observed above certain critical currents, and a large negative-resistance region observed on the decreasmg current leg of the I-V curve. The breakdown phenomenon exhibits a delay time that is a function of the overvoltage applied to the junction, and comparison with nucleation theory has suggested that some type of phase transition is occurring. We suggest a model based on the order-disorder transition that is known to occur in magnetic iron oxide, Fe 3 0 4 . We also discuss possible field ionization processes that could be playing a role in the transition. The sandwiches have been successfully utilized as amplifiers, and can also be set into self-oscillation under certain conditions. Examples of these features are included in the paper. The transition from high to low resistance observed in these sandwiches is similar to those observed in glassy semiconductors at higher temperatures, and certain comparisons may be useful in trying to understand the glassy-semiconductor behavior.

Electroforming and Switching in Oxides of Transition Metals: The Role of Metal–Insulator Transition in the Switching Mechanism

“…The results presented above, as well as the other data on the switching in transition metal oxides (2)(3)(4)(5)(6)(7)(8), indicate that current instabilities with the S-type NR exhibit several…”

“…Threshold switching (without any memory efup from 22 g of benzoic acid (C 6 H 5 COOH) plus 40 ml of fects) with an S-type V-I curve has been observed in the saturated aqueous solution of Na 2 B 4 O 7 per liter of metal-oxide-metal (MOM) structures with Nb 2 O 5 (2,3), acetone (10). Fe, Ti, and several Nb samples were anodized NbO 2 (4,5), TiO 2 (3,6), VO 2 (7), Ta 2 O 5 (3), and Fe oxide in a KNO 3 ϩ NaNO 3 eutectic melt at 570-620 K. The (8). The oxide films were prepared by different methods:…”

Coexistence of Memristance and Negative Differential Resistance in a Nanoscale Metal‐Oxide‐Metal System

“…There have also been multi‐ple reports of current‐controlled negative differential resistance (CC‐NDR) in electroformed MOM devices since the early 1960s (e.g. oxides of V,13–17 Nb,18, 19 Ta,20 Ti,20–23 and Fe24), and there have been a variety of proposals for the physical mechanism. Current work presents persuasive evidence that CC‐NDR in these materials is due to a Joule‐heating induced metal‐insulator transition (MIT) 25, 26.…”

S‐Type Negative Differential Resistance in Semiconducting Transition‐Metal Dichalcogenides

“…In additional to the applications in existing technologies, S-type NDR also shows promising applications in emerging technologies. [14][15][16][17][18][19][20][21][22][23][24][25] However, these mechanisms cannot be shared by most materials, restricting their wider applications. [2][3][4] S-type NDR generated neuron spikes allow for realization of neuromorphic electronic circuits.…”

“…[14][15][16][17][18][19][20][21][22][23][24][25] For this mechanism, NDR does not occur when the ambient temperature is higher than the transition temperature. [14][15][16][17][18][19][20][21][22][23][24][25] For this mechanism, NDR does not occur when the ambient temperature is higher than the transition temperature.…”