Each composition library (Mn-Sb-O, Mn-Sb-Sn-O, Mn-Sb-Ti-O, Mn-Sb-Sn-Ti-O, and Mn-Sb-Co-O) was synthesized via reactive RF magnetron co-sputtering from elemental metal targets (Mn, Sb, Sn, Ti, and Co) in a customdesigned combinatorial sputtering system, and post-deposition annealed in air at 700 °C for 3 h, followed by free cooling to near-ambient temperature. The deposition atmosphere was composed of 4.8 mTorr Ar and 1.2 mTorr O2. The RF powers, as shown in Table , were adjusted to obtain designed composition in the wafer center and the non-confocal geometry of sputter sources provided a continuous composition gradient across 100 mmdiameter Si wafer with thermal oxide, Ti adhesion layer, and Pt conducting layer (Pt/Ti/SiO2/Si substrates).