Functional magnetic oxides for nanomedicine and spin caloritronics

Functional magnetic nanoparticles are currently being explored for several nanomedicine applications including contrast enhancement in MRI and magnetic hyperthermia treatment of cancer. There is a need to improve the specific absorption rate (SAR) and heating efficiency of nanoparticles for hyperthermia and our recent work has focused on the role of surface and interfacial anisotropy with a goal to enhance SAR. We present strategies that go beyond simple spherical structures such as core-shell, exchange-coupled nanoparticles, nanowire, nanotube geometries that can be exploited to increase saturation magnetization, effective anisotropy and heating efficiency in magnetic hyperthermia treatment of cancer cells. In another study we are exploring the generation of pure spin currents in magnetic oxides and their coupling with heat by probing Spin Seebeck Effect (SSE) through systematic Inverse Spin Hall Effect (ISHE) experiments. Our experiments have revealed important correlations between effective magnetic anisotropy on the longitudinal SSE in YIG/Pt structures. There is a critical need to improve the spin mixing conductance across interfaces in SSE structures and devices and our recent work has highlighted strategies to enhance the SSE signal by tuning the interfaces. Overall I will present the importance of surface and interface anisotropy in magnetic materials that can be tuned for obtaining functional responses for a variety of applications.