Self-ordered magnetic <i>α</i>-FeSi2 nano-stripes on Si(111)

Abstract

We fabricated self-assembled one-dimensional α-FeSi2 magnetic nano-stripes, using solid phase epitaxy of ∼1 monolayer Fe on vicinal Si(111) surfaces followed by a 550 °C annealing. Structural and magnetic properties were investigated by scanning tunneling microscopy and superconducting quantum interference device magnetometry, respectively. The nano-stripes show superparamagnetism at room-temperature and at 4 K coercivity about 3 times higher along the long nano-stripe [112¯] direction than along the perpendicular [1¯10] one. The calculated magnetic moment at 4 K was ∼3.3 μB/Fe atom, implying a significant ferromagnetic coupling of the Fe atoms in the system. Such nano-stripes may be useful in high-density magnetic memory storage and spintronics devices.