Interlayer Coupling in Co/Ti/(Gd--Co)/Ti Artificial Layered Ferrimagnet

The magnetic properties and the structure of Co/Ti/Gd_0.36Co_0.64/Ti₄/Co multilayers are investigated by means of torque magnetometer, vibrating sample magnetometer and transverse magneto-optic Kerr effect (TMOKE) measurements and the atomic force microscopy. Due to interlayer exchange interaction, Co and Gd--Co layers form a macroscopic ferrimagnetic system. The change in the sign of the TMOKE hysteresis loops near the compensation temperature and field induced magnetic phase transitions are found. The latter can be characterized by a critical field which shows a linear variation with the temperature. The magnetic properties of these multilayers from many points of view are similar to those of bulk ferrimagnets.