1. Department of Chemistry, Koc University, Rumelifeneri Yolu, Sariyer 34450, Istanbul, Turkey, Graduate School of Materials Science and Engineering, Koc University, Rumelifeneri Yolu, Sariyer 34450, Istanbul, Turkey, and TUBITAK-UME, Magnetic Measurements Lab, PK.54, 41470 Gebze, Kocaeli, Turkey