Magnetic domain configurations and domain dynamics of Co/Pd multilayers

Abstract

Recently, interest in ferromagnetic thin films has grown rapidly motivated by a search for new magnetic materials of technological interest and by their novel magnetic properties. Magnetic domain configurations and domain dynamics in ultrathin ferromagnetic films and multilayers are of fundamental interests, because the nature of domain and domain dynamics in these systems plays a key role in determining their properties such as the domain formation and the magnetization reversal. In this study, we have investigated the magnetic domain configurations and domain dynamics of the Co/Pd multilayered system. To study the magnetic domain dynamics in magnetic thin films, we have developed a high-performance Kerr microscopic system capable of real-time domain observation with the spatial resolution of 0.3 ㎛ and the Kerr angle resolution of 0.2°at ×1,000 magnification. Serial samples of ($t_{Co}-Co/t_{Pd}-Pd)_n$ multilayers have been fabricated by e-beam evaporation with varying the multilayered structure. The magnetic and magnetooptic properties of these samples have been examined by measuring the Kerr hysteresis loops. The generalized domain configurations in ferromagnetic multilayered system have been investigated by considering the magnetostatic energy in multilayered structure. The theory predicts a sharp transition from a large-areal domain pattern to a striped domain configuration with increasing the magnetic layer thickness. This transition was verified experimentally by direct magnetic domain observation in Co/Pd multilayers. On the other hand, we present a generic formalism for an accurate numerical calculation of the magnetic dipolar energy in an arbitrarily shaped ferromagnet uniformly magnetized. The theory predicts the reduction of the magnetostatic energy in thin films having the rough surfaces. We have studied the origins for the contrastive magnetization reversal behavior in thin ferromagnetic films. The magnetization reversal and domain dynamics of...