PAMS Seminar: "Theory-driven Experimental Search of Novel Magnetic Materials for Nanotechnology Applications" by Dr. Dipanjan Mazumdar

Dr. Dipanjan Mazumdar
Southern Illinois University

Abstract:

We are interested in growing new inorganic materials in thin film form and tuning their physical properties through size, chemical doping, interface, and external tuning parameters (light, magnetic field, etc.). In the past few years, my group has focused on the growth and investigation of magnetic thin films for application in emerging nanotechnology areas such as spintronics. This effort has involved several graduate and undergraduate students and led to 2 Master's and 2 PhD’s in the past three and half years. For this talk, after a brief overview of the research area and the desired functional properties, I will present the results of a theory-driven experimental search of novel magnetic materials that potentially support the desired properties. Thermodynamically stable binary and ternary materials were identified in prior theoretical searches in the Heusler family (general formula X2YZ). Among them, we are interested in Mn-based ternary alloys due to their tunable magnetic and crystal properties. Using the magnetron co-sputtering method, we synthesized potentially high-performance Mn3-xFexSn thin films with x= 0, 1, and 2 and evaluated the structural, magnetic, and electrical properties. All samples grew polycrystalline with a hexagonal phase. Electric transport measurements revealed a non-metallic behavior for Mn2FeSn, whereas Fe2MnSn and Mn3Sn showed metallic behavior. Mn3Sn exhibited a low magnetic moment (0.4 µB/f.u). The addition of Fe increased the moment to 3.5 µB/f.u (Mn2FeSn) and 4.7 µB/f.u (Fe2MnSn). Mn2FeSn displayed a large exchange bias effect with the coexistence of antiferromagnetic and ferromagnetic phases below room temperature, whereas Fe2MnSn demonstrated a robust ferromagnetic phase with a Curie temperature of 512 K. Both materials exhibited a sizable magnetic anisotropy of close to 0.5 MJ/m3 at 2 K. Still, only Fe2MnSn is viable for spintronics applications due to its room-temperature functionality.

This is a Zoom seminar: 915 2072 1543

Free