Researchers measure key property of potential spintronic material

Researchers measure key property of potential spintronic material

A team of researchers from Argonne National Laboratory (ANL) and the National Institute of Standards and Technology (NIST) discovered key parameters within an advance material that will enable the next-generation of “spintronic” computers. Constructed by two different compounds, this material promises to allow computers to use the magnetic spin of electrons, in addition to their charge, for computation. It also promises the use of fast memory devices that can use considerably less power than conventional systems and still retain data when the power is off.

Manganite oxide lattices (purple) doped with lanthanum (magenta) and strontium (green) have potential for use in spintronic memory devices, but their usual disorderly arrangement (left) makes it difficult to explore their properties. The ANL/NIST team’s use of a novel orderly lattice (right) allowed them to measure some of the material’s fundamental characteristics. (Credit: Argonne National Laboratory.)

The team engineered a highly ordered version of a magnetic oxide compound that naturally has two randomly distributed elements: lanthanum and strontium. Stronger magnetic properties are found in those places in the lattice where extra lanthanum atoms are added. Precise placement of the strontium and lanthanum within the lattice can enable understanding of what is needed to harness the interaction of the magnetic forces among the layers for memory storage applications, but such control has been elusive up to this point.

So the ANL team was able to develop a method for laying down the oxides one atomic layer at a time, allowing them to construct an exceptionally organized lattice in which each layer contains only strontium or lanthanum, so that the interface between the two components could be studied. The NIST team members then used the NCNR’s polarized neutron reflectometer to analyze how the magnetic properties within this oxide lattice changed as a consequence of the near-perfect placement of atoms.

They found that the influence of electrons near the additional lanthanum layers was spread out across three magnetic layers in either direction, but fell off sharply further away than that. Tiffany Santos, lead scientist on the study from ANL, says that the measurement will be important for the emerging field of oxide spintronics, as it reveals a fundamental size unit for electronic and magnetic effects in memory devices made from the material.

“For electrons to share spin information — something required in a memory system — they will need to be physically close enough to influence each other,” Kirby says. “By ordering this material in such a precise way, we were able to see just how big that range of influence is.”

Call Chad Boutin at 301-975-4261 for more information.

Christina Nickolas