title: Shaping nanoscale magnetic domain memory in exchange-coupled ferromagnets by field cooling.
abstract: The advance of magnetic nanotechnologies relies on detailed understanding of nanoscale magnetic mechanisms in materials. Magnetic domain memory (MDM), that is, the tendency for magnetic domains to repeat the same pattern during field cycling, is important for magnetic recording technologies. Here we demonstrate MDM in [Co/Pd]/IrMn films, using coherent X-ray scattering. Under illumination, the magnetic domains in [Co/Pd] produce a speckle pattern, a unique fingerprint of their nanoscale configuration. We measure MDM by cross-correlating speckle patterns throughout magnetization processes. When cooled below its blocking temperature, the film exhibits up to 100% MDM, induced by exchange-coupling with the underlying IrMn layer. The degree of MDM drastically depends on cooling conditions. If the film is cooled under moderate fields, MDM is high throughout the entire magnetization loop. If the film is cooled under nearly saturating field, MDM vanishes, except at nucleation and saturation. Our findings show how to fully control the occurrence of MDM by field cooling.
authors.affiliation: Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA.
authors.forename: Karine
authors.initials: K
authors.lastname: Chesnel
authors.affiliation: Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Safsten
authors.affiliation: Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Rytting
authors.affiliation: Center for Memory and Recording Research, University of California San Diego, La Jolla, California 92093-0401, USA.
authors.forename: Eric E
authors.identifier: 0000-0002-4725-9509
authors.initials: EE
authors.lastname: Fullerton