Ballistic and Diffuse Electron Transport in Nanocontacts of Magnetics

TL;DR

This paper experimentally investigates the transition from ballistic to diffuse electron transport in Ni nanocontacts during magnetic phase changes, highlighting size-dependent effects on Joule heating and transport modes.

Contribution

It provides new experimental insights into how nanocontact size influences electron transport modes and Joule heating effects during magnetic phase transitions.

Findings

Voltage for Joule heating to critical temperature depends on contact size in ballistic mode.

In diffuse mode, the voltage $U_C$ is independent of contact size.

Reduction in mean free path due to heating can switch transport from ballistic to diffusive.

Abstract

The transition from the ballistic electron transport to the diffuse one is experimentally observed in the study of the magnetic phase transition in Ni nanocontacts with different sizes. It is shown that the voltage $U_C$ needed for Joule heating of the near-contact region to the critical temperature does not depend on the contact size only in the diffuse mode. For the ballistic contact it increases with decrease in the nanocontact size. The reduction of the transport electron mean free path due to heating of NCs may result in change of the electron transport mode from ballistic to diffusive one.