Spin - based three dimensional memory

Abstract

Magnetic memory is the major information storage method for the last sixty years. Since its invention, this technology has undergone very rapid and vast improvements while being challenged by the requirement for higher data storage capacities, for lowering the cost of production and for less power consumption. To supply those demands, the industry constantly tries to develop new techniques. The ultimate goal of the information storage industry is to invent 3D memory systems such that the data are recorded in a three dimensional volume instead of a two dimensional thin lm. In this work, two di erent 3D magnetic memory systems are introduced and experimented. Both of these devices utilize novel concepts of spintronics. First system makes use of a spin-laser and is based on optical magnetization reversal via circularly polarized light. The second system is a multilayer structure where domain walls are moved along ferromagnetic nanowires by the application of spin-polarized current and vertical data shift is achieved through heat assistance. In the rst part of this thesis, the structure and the working principles of the former system, will be introduced and explained as an idea whereas the second part concerns with experiments for realizing the latter system. To fabricate the magnetic multilayer structure, sputter deposition and photolithography are employed. Experiments are carried out for electrical, thermal and magnetic characterization of fabricated thin lms. EDS and XPS are done for stoichiometric analysis of samples. Surface properties are examined via stylus pro ling and AFM. Finally, the distribution of magnetic domains is visualized with MFM. The experimental scope of this study is to establish the preliminary conditions for realizing a 3D magnetic memory structure and demonstrate how this spin-based system operates for the goal of boosting data storage capacity of future information storage devices.