Outreach Programs

Education Programs Technology Outreach Program International Programs Distinguished Lecturer Series International Center for Materials Research MRL Diversity Fellowship MRL Travel Fellowship

Intern: Jennifer Drewes, Chemistry, UC Santa Barbara Mentor: Daniel Shoemaker Faculty Supervisor: Ram Seshadri Department: Materials

SPONTANEOUS FORMATION OF METAL OXIDE MAGNETIC NANOPARTICLE COMPOSITES

We are investigating routes to spontaneously convert a single phase metal oxide system into a two phase system through a series of oxidations and reductions. Since the formation of the two-phase system is spontaneous, this process allows for control of the size and patterning of the nanoparticles by controlling the temperature and rate at which the reactions occur. By producing composites that contain ferromagnetic (FM) and antiferromagnetic (AFM) phases, we expect that exchange bias will be observed due to interfacial interactions. Exchange bias is the coupling effect that occurs at a FM-AFM interface when the system is cooled in the presence of a static magnetic field. Exchange bias results in a shift of a system’s hysteresis loop along the field axis, usually in the negative direction. We have characterized composites and ternary oxides solid solutions of Cr, Mn, Fe, Co, and Ni using x-ray diffraction, Rietveld refinement, thermogravimetric analysis, and scanning electron microscopy.

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