UCLA

Magnetic nanomaterials are an important and widely studied class of materials with a wide variety of applications. The work presented here is aimed at both developing techniques to control the nanoscale structure of these materials and understanding the relationship between that structure and the overall material properties. The techniques used here are primarily solution-phase methods which offer a high degree of control and versatility.

The first part of this work is focused on thin films of magnetic oxide materials which are particularly applicable to radio frequency (RF) devices. Here, both sol-gel and nanocrystal precursors are used to create thin films where the film composition, grain size and porosity are controllably tuned. We then investigated both the static and dynamic magnetic properties of the films to better understand how the nanoscale structure impacts the overall properties. These investigations provide valuable insights that can allow us to design materials with properties tailored to meet the requirements of individual devices. Importantly, these insights are applicable to a wide variety of magnetic materials and are not limited to the specific materials studied here.

The second part of this work is focused on metallic alloy nanocrystals which have potential applications as elements in high density data storage devices. First, in chapter 5, the magnetoelectric properties of FePd nanocrystals is investigated. FePd is a good candidate for use in magnetoelectric memory devices which are highly energy efficient. By using nanocrystals of FePd, we hope to find a route to potentially reducing bit size in those devices which can lead to increased data storage densities. Then, in chapter 6, we move on to explore shape effects by looking at FePt nanorods. FePt has a very high magnetic anisotropy which in memory devices translates to increased bit stability and potentially allows for smaller bit sizes. In nanorods, shape anisotropy can enhance the already high magnetic anisotropy to create even stronger nanomagnets.