Researchers find cheaper way to create textured nickel ferrite

Researchers from North Carolina (NC) State University and the Georgia Institute of Technology have demonstrated a less expensive way to create textured nickel ferrite (NFO) ceramic thin films.

NFO is a magnetic material that holds promise for applications in microwave technologies or next-generation memory devices and the new process is claimed to be easily scalable to address manufacturing needs.

According to a statement from NC State, this is the first time researchers have used a chemical deposition process to create NFO thin films that are textured, meaning they have an aligned crystalline structure. Arraying the crystalline structure in such a way maximises the magnetic properties of the material.

Using a chemical deposition process also makes it easier to modify, or dope, the NFO by adding additional materials, such as zinc.

By doping the NFO, researchers can optimise the material for various applications. For example, adding zinc allows the NFO to retain its magnetic properties at higher temperatures.

The technique used to create the NFO thin films begins by introducing nickel and iron compounds into an organic solvent to create an NFO solution.

The solution is then injected onto a silicon wafer that has been coated with platinum.

The wafer is then spun, spreading the solution uniformly across the wafer’s surface. The wafer is heated to evaporate the solvent, then heated again to 750°C to crystallise the NFO.

‘This approach can be used to deposit textured NFO thin films over areas at least as large as 10cm by 10cm,’ said Dr Justin Schwartz, co-author of a paper on the research and Kobe Steel Distinguished Professor and department head of the Materials Science and Engineering Department at NC State.

Previous efforts to create textured NFO thin films are said to have relied on techniques that can only deposit such thin films over a small area.

The paper, Growth of (111) oriented NiFe2O4 polycrystalline thin films on Pt (111) via sol-gel processing, was published online in September in the Journal of Applied Physics.