Magneto-transport Properties of Two-dimensional Co Anti-dot Arrays

Abstract

We fabricated two-dimensional Co anti-dot arrays, square-lattice structure of 1.02-mu m-diameter circular holes with a periodicity of 1.60 mu m, on a silicon substrate by using the CMOS (complementary metal-oxide semiconductor) process. The X-ray diffraction data indicate that the anti-dot arrays constitute an exchange-biased system that consists of vertical ferromagnetic Co layers interfaced with antiferromagnetic Co-oxide layers. We found an anomaly in the temperature dependence of the resistivity at temperatures below the Neel temperature of CoO. We also found exchange-biased behaviors in both the magnetization curves and the magneto-transport data. By extracting the exchange-bias fields of the anti-dot array, we found that the exchange bias for the longitudinal magnetic field was much larger than that for the transverse field, which might be attributed to the spin-transfer effect.