Guneeta Singh-Bhalla

Built-in and induced polarization across LaAlO3/SrTiO3 heterojunctions

Ionic crystals terminated at oppositely charged polar surfaces are inherently unstable and expected to undergo surface reconstructions to maintain electrostatic stability. Essentially, an electric field that arises between oppositely charged atomic planes gives rise to a built-in potential that diverges with thickness. Here we present evidence of such a built-in potential across polar LaAlO{sub 3} thin films grown on SrTiO{sub 3} substrates, a system well known for the electron gas that forms at the interface. By performing tunneling measurements between the electron gas and metallic electrodes on LaAlO{sub 3} we measure a built-in electric field across LaAlO{sub 3} of 80.1 meV/{angstrom}. Additionally, capacitance measurements reveal the presence of an induced dipole moment across the heterostructure. We forsee use of the ionic built-in potential as an additional tuning parameter in both existing and novel device architectures, especially as atomic control of oxide interfaces gains widespread momentum.

Growth and characterization of multiferroic BiMnO3 thin films

We have grown epitaxial thin films of multiferroic BiMnO

Colossal magnetocapacitance and scale-invariant dielectric response in phase-separated manganites

_3

Contribution of interface capacitance to the electric-field breakdown in thin-film Al–AlOx–Al capacitors

using pulsed laser deposition. The films were grown on SrTiO

Intrinsic tunneling in phase separated manganites.

_3

Unexpected Termination Switching and Polarity Compensation in LaAlO3/SrTiO3 heterostructures

(001) substrates by ablating a Bi-rich target. Using x-ray diffraction we confirmed that the films were epitaxial and the stoichiometry of the films was confirmed using Auger electron spectroscopy. The films have a ferromagnetic Curie temperature (

Understanding polarity compensation across polar LaAlO

T_C

_3

) of 85

films

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Probing interface reconstructions in multiferroic BiFeO

5 K and a saturation magnetization of 1