Ballistic magnetoresistance in a magnetic nanometer sized contact: An effective gate for spintronics

Abstract

We present experimental results of unprecedented large magnetoresistance obtained in stable electrodeposited Ni–Ni nanocontacts 10–30 nm in diameter. The contacts exhibit magnetoresistance of up to 700% at room temperature and low applied fields and, therefore, act as very effective spin filters. These large values of the magnetoresistance are attributed to spin ballistic transport through a magnetic "dead layer" at the contact of width of about 1 nm or smaller. Nanometer sized, high sensitive magnetoresistive sensors could become key elements for magnetic storage in the terabit/in.2 range and in high density magnetic random access memories.