Research Projects

Double perovskites (DP's) are quaternary oxides with the general formula A2BB′O6 and are structural variants of perovskites (ABO3). They possess a wide variety of magnetic, electrical, and magneto-transport properties, including room temperature ferromagnetism, giant magnetocaloric effect, metal-insulator transition, and half-metallicity. Room temperature DP ferromagnets often require high pressure or high temperatures to prepare in bulk form, while thin films can be grown using pulsed laser deposition with smaller pressure and reduced temperatures. Tuning magnetic anisotropy towards out-of-plane is important for applications, and studying the thickness evolution of magnetic anisotropy is crucial. Controlling magnetocrystalline anisotropy allows for local control of magnetization, which is used to make novel spintronic devices. The role of interfacial strain on the magnetism of ultrathin DP's will help design ferromagnets for applications. The goal is to study magnetocrystalline anisotropy, shape anisotropy, and induced anisotropy in DP's. Six important DP systems with the generic formula A2BB'O6 will be grown and studied for the evolution of magnetic anisotropy with respect to thickness, strain, and growth temperature. To probe the magnetism of ultrathin magnetic samples, a home-built Magneto-Optical Kerr effect (MOKE) will be developed and studied to obtain perpendicular magnetic anisotropy. This technique uses an optical modulation technique, which is surface sensitive and can easily avoid the substrate effect.