Magnetic properties of single-crystalline CoSi nanowires.
We have observed unusual ferromagnetic properties in single-crystalline CoSi nanowire ensemble, in marked contrast to the diamagnetic CoSi in bulk. High-density freestanding CoSi nanowires with B20 crystal structure are synthesized by a vapor-transport-based method. The reaction of cobalt chloride precursor with a Si substrate produces high-aspect-ratio CoSi nanowires. The high-resolution transmission electron microscopy and electron diffraction studies reveal superlattice structure in CoSi nanowires with twice the lattice parameter of simple cubic CoSi lattice. The zero-field-cooled and field-cooled (ZFC-FC) measurements from the nanowire ensemble show freezing of the disordered surface spins at low temperatures. The magnetoresistance (MR) measurements of single nanowire devices show a negative MR whose magnitude gets larger at lower temperatures.
Seo
Kwanyong
K
Department of Chemistry, KAIST, Daejeon 305-701, Korea.
Varadwaj
K S K
KS
Mohanty
Paritosh
P
Lee
Sunghun
S
Jo
Younghun
Y
Jung
Myung-Hwa
MH
Kim
Jinhee
J
Kim
Bongsoo
B