Anisotropic transport and Negative Resistance in a polycrystalline metal-semiconductor (Ni-TiO2) hybrid

TL;DR

This study explores the unusual electrical transport phenomena in a Ni-TiO2 hybrid system, revealing anisotropic conduction and negative resistance linked to its nanostructure and phase transitions, with implications for modeling complex hybrid materials.

Contribution

It provides new insights into the anisotropic transport and negative resistance in a polycrystalline Ni-TiO2 hybrid, highlighting the role of nanostructure and phase transitions.

Findings

Insulator to metal transition below 150 K.

Observation of negative resistance in the metallic phase.

Anisotropic conduction due to dendritic TiO2 and Ni nanoparticles.

Abstract

We investigate anomalous electrical transport properties of a Ni-TiO2 hybrid system displaying a unique nanostructured morphology. The system undergoes an insulator to metal transition below 150 K with a low temperature metallic phase that shows negative resistance in a four-probe configuration. Temperature dependent transport measurements and numerical modelling show that the anomalies originate from the dendritic architecture of the TiO2 backbone interspersed with Ni nanoparticles that paradoxically renders this polycrystalline, heterogeneous system highly anisotropic. The study critiques inferences that may be drawn from four-probe transport measurements and offers valuable insights into modelling conductivity of anisotropic hybrid materials.