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PI: Don Heiman
Authors: Li Zhang, Darius Basiaga, Romain Scheck, Joshua Rau, Don Heiman
Presenters: Li Zhang
Primary Contact: Don Heiman
Primary Contact’s E-mail: d.heiman@neu.edu
Primary Contact’s Phone: x2912

Nanostructures Lead to New Ferromagnetic Materials

Future electronic devices for information technology are predicted to take advantage of the magnetic moment of the electron, in addition to the charge of the electron as used in present day semiconductor electronics. It therefore crucial to be able to synthesize new nanostructures which combine ferromagnets with semiconductors. We have synthesized novel ferromagnetic cobalt materials which are compatible with the important semiconductor GaAs. This discovery will eventually lead to compound ferromagnetic/semiconducting devices fabricated in our laboratory. Among these devices are ultra-sensitive magnetic field sensors for applications in magnetic storage devices, LED light emitting devices which produce circularly polarized light, and perhaps “spintronic” devices for future quantum computers. Synthesis of these compound nanostructures takes place in our Molecular Beam Epitaxy (MBE) crystal growth facility in the Egan Center. In this facility we grow nanolayers of materials as small as a few atoms (1 nanometer) thick. In such thin layers the properties of the materials can be remarkably different from the same materials which are much thicker. For example, we have found that by laying down a mixture of Co and Mn on GaAs we can produce thin layers of ferromagnetic material which would normally be antiferromagnetic. This gives rise to a much wider phase diagram (TC vs x) for Co1-XMnX, up to x=0.8. We have also produced another unique ferromagnet, Co2MnAl, which is matched to GaAs and is strongly ferromagnetic at room temperature. Work is in progress to understand the properties of these new materials and incorporate them into devices.