NER: Interplay of Magnetism and Superconductivity at the Nanometer Scale

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

This is a Nanoscale Exploratory Research (NER) award for a proposal submitted through the Nanoscale Science and Engineering solicitation. A theoretical program will be initiated to explore the interplay of magnetism and superconductivity in complex oxide nanostructures. The research is highly exploratory due to the complexity of the materials involved. Until very recently, conventional wisdom in any engineered nanostructure dictated that magnetism should completely destroy superconductivity at the nanometer scale. However, experimental efforts in the past year have shown that coexistence of magnetism and superconductivity is possible in Manganese-oxide/Cuprate-oxide nanometer scale heterostructures with characteristic length scales less than sixty nanometers. This is in sharp contrast to many heterostructures made of conventional magnets and conventional superconductors, where the interplay of superconductivity and magnetism has been studied. In this case the conclusion was that superconductivity and magnetism could not coexist at the nanometer scale , and certainly not at temperatures above forty Kelvin. The discovery of the coexistence in Manganses-oxide/Cuprate-oxide nanostructures leads to several important intellectual issues that need to be addressed at the nanometer scale. These issues include understanding of fundamental aspects like the magnetic proximity effect on d-wave superconductivity, the superconducting (d-wave) proximity effect on half-metallic ferromagnets, the stabilization of long-range superconducting and magnetic order in multilayers (experimentally available for complex oxides), and lateral wires and quantum dot arrays (not experimentally available for complex oxides). Nanoscale device concepts will also be proposed which rely on the interplay of Cuprate-oxide superconductivity and Manganese-oxide magnetism at the nanometer scale. One such device concept is called the super-colossal magneto-resistance switch . Work on ultra-thin heterostructures will lead to better understanding of nanostructures currently available. %%% This is a Nanoscale Exploratory Research (NER) award for a proposal submitted through the Nanoscale Science and Engineering solicitation. A theoretical program will be initiated to explore the interplay of magnetism and superconductivity in complex oxide nanostructures. The research is highly exploratory due to the complexity of the materials involved. Until very recently, conventional wisdom in any engineered nanostructure dictated that magnetism should completely destroy superconductivity at the nanometer scale. However, experimental efforts in the past year have shown that coexistence of magnetism and superconductivity is possible in Manganese-oxide/Cuprate-oxide nanometer scale heterostructures with characteristic length scales less than sixty nanometers. Nanoscale device concepts will also be proposed which rely on the interplay of Cuprate-oxide superconductivity and Manganese-oxide magnetism at the nanometer scale. One such device concept is called the super-colossal magneto-resistance switch . Work on ultra-thin heterostructures will lead to better understanding of nanostructures currently available. ***