C. B. Eom

Coexistence of superconductivity and ferromagnetism in two dimensions.

Ferromagnetism is usually considered to be incompatible with conventional superconductivity, as it destroys the singlet correlations responsible for the pairing interaction. Superconductivity and ferromagnetism are known to coexist in only a few bulk rare-earth materials. Here we report evidence for their coexistence in a two-dimensional system: the interface between two bulk insulators, LaAlO(3) (LAO) and SrTiO(3) (STO), a system that has been studied intensively recently. Magnetoresistance, Hall, and electric-field dependence measurements suggest that there are two distinct bands of charge carriers that contribute to the interface conductivity. The sensitivity of properties of the interface to an electric field makes this a fascinating system for the study of the interplay between superconductivity and magnetism.

Giant piezoelectricity on Si for hyperactive MEMS.

High-quality piezoelectric thin films are grown and exhibit superior properties for microelectromechanical systems. Microelectromechanical systems (MEMS) incorporating active piezoelectric layers offer integrated actuation, sensing, and transduction. The broad implementation of such active MEMS has long been constrained by the inability to integrate materials with giant piezoelectric response, such as Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT). We synthesized high-quality PMN-PT epitaxial thin films on vicinal (001) Si wafers with the use of an epitaxial (001) SrTiO3 template layer with superior piezoelectric coefficients (e31,f = –27 ± 3 coulombs per square meter) and figures of merit for piezoelectric energy-harvesting systems. We have incorporated these heterostructures into microcantilevers that are actuated with extremely low drive voltage due to thin-film piezoelectric properties that rival bulk PMN-PT single crystals. These epitaxial heterostructures exhibit very large electromechanical coupling for ultrasound medical imaging, microfluidic control, mechanical sensing, and energy harvesting.

High-field superconductivity in alloyed MgB 2 thin films

We investigated the effect of alloying on the upper critical field

Strain modification of epitaxial perovskite oxide thin films using structural transitions of ferroelectric BaTiO3 substrate

H_{c2}

Synthesis and ferroelectric properties of epitaxial BiFeO3 thin films grown by sputtering

in 12

Creation of a two-dimensional electron gas at an oxide interface on silicon

MgB_2

Weak-link behavior of grain boundaries in superconducting Ba(Fe1−xCox)2As2 bicrystals

films, in which disorder was introduced by growth, carbon doping or He-ion irradiation, finding a significant

Polarization switching in epitaxial BiFeO3 films

H_{c2}

Prediction of ferroelectricity in BaTiO3/SrTiO3 superlattices with domains

enhancement in C-alloyed films, and an anomalous upward curvature of

Growth of (103) fiber-textured SrBi2Nb2O9 films on Pt-coated silicon

H_{c2}(T)