The nanofabrication and transport properties of ferromagnetic metal nanocontacts

Abstract

In this paper, the invar alloy nanocontact structures with different widths were fabricated using the electron beam lithography (EBL) and lift-off technique. Through the I– V measurement, we found that a domain wall (DW) could be pinned at the contact position and pushed away by the spin-polarized current when the width of nanocontact less than 300 nm, which induced the change of the nanocontact resistance, i.e., domain wall magnetoresistance (DWMR). The DWMR decreased with the increase of the contact width, but the critical current density kept constant for the different contact widths, which was about 1.8 × 10 7 A/cm 2. For the string nanostructure with several different widths of nanocontact, the domain wall was pushed away one by one with increasing spin-polarized current. However, the domain walls were pushed away simultaneously for the string nanostructure with the same width of nanocontact and a larger DWMR could be obtained in this kind of nanostructure. Based on the controlling to domain wall motion in nanocontacts, the potential application for ferromagnetic metal nanocontacts on the magnetic logic gate was possible.