STUDY OF SEQUENTIALLY SPUTTERED Co-HfO2 GRANULAR FILMS

Abstract

Magnetic granular films (GFs) have potential sensor applications due to superparamagnetism and magnetoresistance properties. Co-HfO2 granular films were fabricated using sequential sputtering and their structural, magnetic, and electrical properties were studied systematically to investigate the grain growth model of sequential sputtering as a function of deposition conditions. An imaging method based on the conductive atomic force microscopy (CAFM) was developed to image the nanostructure of the Co-HfO2 GFs. A control sample using patterned and well-defined Py nanostructures was studied to test the imaging capability of CAFM and build a model. Tomography and 3D image reconstruction of the Co-HfO2 GFs were also developed based on the CAFM imaging characterization, which allowed the dimensions of the grains to be quantified in both the lateral and vertical direction and show that sequential-sputter technique can control the growth of the NPs in the lateral and vertical direction as a function of deposition conditions.