Magnetic Configurations of 30 nm Iron Nanocubes Studied by Electron Holography

• Published in: Nano letters Vol. 8; no. 12; pp. 4293 - 4298
• Main Authors: Snoeck, E, Gatel, C, Lacroix, L. M, Blon, T, Lachaize, S, Carrey, J, Respaud, M, Chaudret, B
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.12.2008
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetic properties and materials; Magnetic properties of nanostructures; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Small particles and nanoscale materials; Studies of specific magnetic materials; Magnetic flux; Data storage; Ferromagnetic materials; Iron; Dipole interactions; Technological application; Electron holography; Monocrystals; Transmission electron microscopy; Magnetic storage devices; Bending; Nanostructured materials; Magnetic properties
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl801998x

Ferromagnetic nanomaterials exhibit unique magnetic properties common to materials with dimensions approaching the atomic scale and have potential applications in magnetic data storage. Technological applications, however, require that the detailed magnetic behaviors and configurations of individual and interacting magnetic nano-objects be clarified. We determined the magnetic remnant configurations in single crystalline 30 nm Fe nanocubes and groups of nanocubes using off-axis electron holography in a transmission electron microscope. Our measurements on an isolated cube reveal a vortex state whose core size has been determined. Two neighboring nanocubes with adjacent {100} surfaces exhibit a ferromagnetic dipolar coupling, while similar magnetic interactions between four cubes in a square arrangement induce a bending of the magnetic induction, i.e., a magnetic flux closure state. The various configurations were successfully simulated by micromagnetic calculations.