Another spin in the wall : domain wall dynamics in perpendicularly magnetized devices

The world as we know it today would be completely different without spintronics. It has revolutionized the way we carry, store and exchange information in our daily lives. What is it? It is a research realm that combines the fundamental property of the electron, spin, and the charge property driving conventional electronics, hence: spin-tronics. Spintronics has until recently concentrated mainly on the manipulation of chargecurrent through the control of the magnetic state. Currently, a new paradigm has emerged that reverses this idea, basically by applying Newton’s law of action implies reaction. Instead of manipulating the charge-current by the magnetic state, it manipulates the magnetic state by a spin-polarized current, and it is gradually gaining interest. Spin-polarized current induced motion of a magnetic domain wall is the subject of this thesis.We try to use a spin polarized current to push a magnetic domain wall. The interaction between spin-current and the magnetic domain wall is still an open area for exploration; there are still many unanswered questions on the fundamental physics that brings it about. The prospect of new data storage, memory and even bio-related devices makes it a very lively and competitive research topic possibly relevant in shaping our future world. We chose perpendicularly magnetized devices as our material, and for a reason. In this class of materials the magnetic domain walls are very narrow; and this, was our assumption, should increase the interaction between the spin polarized current and the magnetization. Our research has made use of a great variety of experimental and nano-fabrication techniques. Since the nano-fabrication techniques were particularly new to our research group, they have been given ample attention in chapter 2. The material used in our research are perpendicularly magnetized ultrathin Co(FeB) layers (