Absence of ballistic magnetoresistance in Ni contacts controlled by an electrochemical feedback system

Abstract

We have developed an electrochemical system to allow the deposition of a magnetic nanocontact whose resistance can be systematically varied between approximately and . We use a thin-film geometry that suppresses the magnetostrictive artifacts possible in the classic two-wire geometry. The control system has allowed magnetoresistance measurements of fragile contacts to be made under stable electrochemical conditions. No evidence of ballistic magnetoresistance was found within this range of resistance at any field orientation.