Structural, electrical and magnetic properties of Fe network films grown on nanochannel Al_2O_3 substrates by direct current magnetron sputtering with the oblique target

摘要

Fe films were deposited on nanochannel Al_2O_3 substrates at 300 K by direct current magnetron sputtering with the oblique target. The film thickness is 100nm, 120nm, 175nm and 325 nm. All the films consist of granules and grow with a network structure. The network structure is formed by granule connection. The granule consists of many fine grains. The granule size increases with increasing film thickness. The transverse width of the granule gradually widens along the film growing direction. The 120nm-thick film has a honeycomb-like network structure. The network films have a resistivity of about 7 × 10~(-5) Ωm. A temperature dependence of the resistivity within 1.5-200 K reveals that the Fe network films exhibit a minimal resistivity at about 30 K. A logarithmic temperature dependence of the conductance is verified at temperatures below 30 K. The 100 nm-thick film exhibits the weakest magnetocrystalline anisotropy and magnetic uniaxial anisotropy. The 120 nm-thick film has the lowest coercivity.