Size and shape evolution of embedded single-crystal α -Fe nanowires

The size and shape evolution of embedded ferromagnetic α -Fe nanowires is discussed. The α -Fe nanowires are formed by pulsed-laser deposition of La0.5 Sr0.5 FeO3-x on single-crystal SrTiO3 (001) substrate in reducing atmosphere. The average diameter of the nanowires increases from d≈4 to 50 nm as the growth temperature increases from T=560 to 840 °C. Their in-plane shape evolves from circular to octahedral and square shape with [110] facets dominating as the growth temperature increases. A fitting to a theoretical calculation shows that the circular shape is stable when the diameter of the nanowires is smaller than 8 nm. © 2005 American Institute of Physics.