Structural and magnetic properties of Co∕Pt(111) with Ni buffer layers

Abstract

Structural and magnetic properties of a chemically ordered face-centered-cubic (111) Mn alloy filmMagneto-optical Kerr effect, low-energy electron diffraction, and Auger electron spectroscopy were used to investigate the magnetic properties and the growth mode of ultrathin Co films deposited on 1 ML ͑monolayer͒ Ni/ Pt͑111͒ at room temperature. No Kerr signal was observed when the thickness of Co film was below 3 ML, and the easy axis of the magnetization was in plane when the thickness of Co was greater than 3 ML at room temperature. The polar Kerr signal appeared after the sample was annealed at 450 K for 1 ML of Co. Further studies in the magnetic properties and surface composition of 3 ML Co/1 ML Ni/ Pt͑111͒ during an annealing process showed that the out-of-plane magnetization enhances significantly when Co and Ni atoms diffuse into the Pt substrate. The coercivity of the system can be adjusted by changing the annealing temperature. Measuring at room temperature, the coercivity increases when the annealing temperature rises. The possible mechanism of the evolution of magnetic properties with the structure of the interface is discussed.

Alloy formation of Co/Ni/Pt(111)

“…Then Co atoms were deposited on the 1 ML Ni/ Pt(1 1 1). The initial growth of Co films on 1 ML Ni/ Pt(1 1 1) was a 2-ML layer-by-layer mode, after which it turned into a 3-D island growth [10]. AES is a suitable technique to study surface diffusion during the heating process.…”

Surface Structural and Magnetic Properties of Cobalt Bilayer Deposited on Pt(111) with Ni Buffer Layer

“…The growth of 2 MLs of Co on 1 ML of Ni/Pt(111) occurred layer by layer at room temperature. 18) It has been reported that, for as-deposited Co/1 ML Ni/Pt(111) films, neither the polar nor longitudinal Kerr rotations can be observed when the thickness of the Co film is below 3 MLs. The easy axis of magnetization is in the in-plane direction when the thickness of the Co film is greater than 3 MLs.…”

“…The easy axis of magnetization is in the in-plane direction when the thickness of the Co film is greater than 3 MLs. 18) To investigate the effects of the Ni buffer layer and the thickness of Co films on the magnetic properties, the evolutions of polar remnant Kerr rotations (M R ) of 2 ML Co/Pt(111), 1 ML Co/1 ML Ni/Pt(111), and 2 ML Co/Pt(111) versus the sample temperature (T S ) after annealing at 750 and 850 K for 20 min are shown in Fig. 1.…”