Magnetic properties in Mn/Si-O/Si(100)-substrate systems and Mn/Si-O/Si trilayers

We have investigated the magnetic properties of Mn/Si-O/Si(100)-substrate systems and Mn/Si-O/Si trilayers. The Mn/Si-O/Si(100)-substrate systems show ferromagnetism after annealing at temperatures above 570K, although the as-deposited systems are not ferromagnetic. The Mn/Si-O/Si trilayers also show ferromagnetism after annealing, and the highest saturation magnetization is obtained at a Si-O thickness of 2.5 nm. Changes in saturation magnetization due to temperature show that the Mn/Si-O/Si trilayers have two kinds of ferromagnetic compounds with different Curie temperatures.