Room temperature exchange bias and spin valves based on $BiFeO3∕SrRuO3∕SrTiO3∕Si$ (001) heterostructures

We report the growth and characterization of exchange bias and spin valve heterostructures based on the multiferroic antiferromagnet $BiFeO3$ on Si (001) substrates. Using $Co0.9Fe0.1$ as the ferromagnet, we demonstrate heterostructures with large negative exchange bias and negligible training (or a decrease in exchange bias field as a function of repeated magnetic cycling) at room temperature. We additionally report the manufacture of spin valve structures that have been found to have current in-plane magnetoresistance of over 2.25% at room temperature.