We have studied the magnetic coupling between two continuous Fe layers of fixed thickness separated by a granular Fe-SiO 2 spacer of varying thickness (1.1 nm < t < 18 nm) and composition (0.45 < x < 0.95). We have analyzed the magnetic response with dc magnetization and ferromagnetic resonance (FMR). Depending on the characteristics of the Fe-SiO 2 layer the hysteresis loops can have a continuous or a two step process reversal. FMR data show one or two absorption lines, depending on the microwave excitation frequency. From these data we were able to determine that the Fe/Fe interlayer coupling is ferromagnetic with an exchange field in the range of 0.5 kOe < H E < 3.5 kOe. The largest coupling occurs for thin spacers and large Fe concentrations. Fe/Fe-SiO 2 layers are also coupled ferromagnetically with an exchange coupling constant that is larger than the Fe/Fe interlayer interaction.
ASJC Scopus subject areas
- Physics and Astronomy(all)