Microwave spectroscopic studies of obliquely deposited Co/Cr trilayers

Abstract

Polycrystalline Co/Cr trilayers were grown by e-beam evaporation in ultra-high vacuum, with Co deposited at various oblique angles to the substrate. Microwave spectroscopic experiments were performed with the applied field in the in-plane and out-of-plane configurations to explore the resultant changes in anisotropy and interlayer coupling. The in-plane anisotropy, effective magnetisation and interlayer coupling strength are found to be greatly affected by the angle of Co deposition. In addition, it is found that samples deposited at intermediate angles exhibit absorption spectra which are more complicated than the two lines expected in a trilayer structure. This phenomenon is not fully understood at present, but may be due to the presence of Co atoms in the Cr interlayer. It can be concluded that the magnetic properties of these structures depend critically on the angle of deposition, and that the magnetic anisotropy and coupling can be modified by an appropriate choice of angle.