Size effects in ordered arrays of magnetic nanotubes: pick your reversal mode

Ordered arrays of magnetic nanotubes are prepared by combining a porous template (anodic alumina) with a self-limiting gas-solid chemical reaction (atomic layer deposition). The geometric parameters can thus be tuned accurately (tube length of 1–50 μm, diameter of 20–150 nm, and wall thickness of 1–40 nm), which enables one to systematically study how confinement and anisotropy effects affect the magnetic properties. In particular, the wall thickness of such ordered Fe3O4 nanotubes has a nonmonotonic influence on their coercive field. Theoretical models reproduce the size effects that are experimentally observed and interpret them as originating from a crossover between two distinct modes of magnetization reversal.

[1]  J. Escrig,et al.  Crossover between two different magnetization reversal modes in arrays of iron oxide nanotubes , 2008, 1106.2833.

[2]  Mato Knez,et al.  Synthesis and Surface Engineering of Complex Nanostructures by Atomic Layer Deposition , 2007 .

[3]  Hao Shen,et al.  Ordered iron oxide nanotube arrays of controlled geometry and tunable magnetism by atomic layer deposition. , 2007, Journal of the American Chemical Society.

[4]  J. Escrig,et al.  Reversal modes in magnetic nanotubes , 2006, cond-mat/0611234.

[5]  C. Ross,et al.  Magnetostatic interactions of single-domain nanopillars in quasistatic magnetization states , 2005 .

[6]  Christopher G Thanos,et al.  Nanotechnology and medicine , 2003, Expert opinion on biological therapy.

[7]  Taeghwan Hyeon,et al.  Chemical synthesis of magnetic nanoparticles. , 2003, Chemical communications.

[8]  Fernando Luis,et al.  Magnetization reversal of ferromagnetic nanowires studied by magnetic force microscopy , 2003 .

[9]  H. A. M. van den Berg,et al.  Ultrafast precessional magnetization reversal by picosecond magnetic field pulse shaping , 2002, Nature.

[10]  Ralf B. Wehrspohn,et al.  Self-ordering Regimes of Porous Alumina: The 10% Porosity Rule , 2002 .

[11]  Stuart A. Wolf,et al.  Spintronics: A Spin-Based Electronics Vision for the Future , 2001, Science.

[12]  Riccardo Hertel,et al.  Micromagnetic simulations of magnetostatically coupled Nickel nanowires , 2001 .

[13]  P. Tiberto,et al.  Granular Cu-Co alloys as interacting suparparamagnets , 2001 .

[14]  Ralf B. Wehrspohn,et al.  Hexagonally ordered 100 nm period nickel nanowire arrays , 2001 .

[15]  K. Guarini,et al.  Ultrahigh-density nanowire arrays grown in self-assembled diblock copolymer templates. , 2000, Science.

[16]  M. C. Abraham,et al.  Magnetic force microscopy study of interactions in 100 nm period nanomagnet arrays , 2000 .

[17]  Sun,et al.  Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices , 2000, Science.

[18]  R. Cowburn,et al.  Single-Domain Circular Nanomagnets , 1999 .

[19]  William J. Gallagher,et al.  Magnetization Reversal in Micron-Sized Magnetic Thin Films , 1998 .

[20]  Kenji Fukuda,et al.  Ordered Metal Nanohole Arrays Made by a Two-Step Replication of Honeycomb Structures of Anodic Alumina , 1995, Science.

[21]  Chen,et al.  Enhanced magnetization of nanoscale colloidal cobalt particles. , 1995, Physical review. B, Condensed matter.

[22]  M. Sharrock,et al.  Time dependence of switching fields in magnetic recording media (invited) , 1994 .

[23]  Lee,et al.  Magnetization curling reversal for an infinite hollow cylinder. , 1994, Physical review. B, Condensed matter.

[24]  C. Chien,et al.  Fabrication and Magnetic Properties of Arrays of Metallic Nanowires , 1993, Science.

[25]  E. Wohlfarth,et al.  A mechanism of magnetic hysteresis in heterogeneous alloys , 1948, Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences.

[26]  I. Schuller,et al.  Ordered magnetic nanostructures: fabrication and properties , 2003 .