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INTEGRATION OF FERROMAGNETIC METALS IN VERTICALLY ALIGNED NANOSTRUCTURES FOR SPINTRONICS
Vertically aligned nanocomposite (VAN) thin films are a promising thin-film platform that allows the combination of a highly desired material with another complementary oxide. Traditionally, VANs have been limited to combining an oxide with another oxide which has shown a wide range of functionality, and, by adjusting the different growth parameters, it has led to the tuning of their physical properties. While VANs have already shown to be an effective platform with immense potential, further enhancement of physical properties can be performed by replacing one of the oxides with a metal forming metal-oxide VANs.
In this dissertation, by the inclusion of the 3d transition metals, e.g., Fe and Co, into various oxide matrices, such as La0.5Sr0.5FeO3, BaZrO3, and BaTiO3, strong, highly anisotropic, ferromagnetic properties have been achieved. By varying the growth parameters, tunable physical properties, mainly coercivity and anisotropic ratio, have been demonstrated. Furthermore, in the case of Co-BaZrO3, a multi-layer stack has been successfully grown and demonstrated a tailorable magnetoresistance. Additionally, a novel system by combining Fe pillars into a BaTiO3 matrix has been demonstrated. This new system allows for the combination of the room temperature Fe ferromagnetic properties with the ferroelectric properties of BaTiO3, allowing for coupling between the two with coercivity tuning and tailorable ferromagnetic properties.
Lastly, it has been shown a possible framework by adding additional metals into the existing metal-oxide VAN platform. By adding the third phase, another metal, it opens up a new avenue to induce additional functionality while creating a method to introduce coupling between the different metals and physical properties.