Magnetoresistance of nickel nanocontacts fabricated by different methods

Abstract

Nickel nanocontacts have been fabricated by focused ion-beam FIB milling of e-beam patternedplanar contacts, FIB milling of conical-shaped nanoperforations in a silicon nitride membrane, andnanoimprinting using an atomic force microscope. Their sizes ranged from 1 to 30 nm.Magnetoresistance of up to 3% is developed in a field of a few millitesla. This is interpreted in termsof ballistic magnetoresistance across a wide domain wall whose structure is determined by dipolarinteractions at the contact.