Functional magnetic oxides for biomedical applications and spin caloritronics
ABSTRACT :
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 magnetic anisotropy and switching fields 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. Our recent work has also shown how introducing organic C60 layers have a big influence in enhancing the SSE signal. Overall I will present the importance of surface and interface anisotropy in magnetic materials that can be tuned for obtaining interesting functional responses for a variety of applications.