Siwei Tang1 2 3 Ivan Kravchenko3 Thomas Ward3 Qiang Zou3 Anping Li3 David Mandrus2 Zheng Gai3

1, Central South University, Changsha, Hunan, China
2, University of Tennessee, Knoxville, Knoxville, Tennessee, United States
3, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States

Single-crystal iron germanium nanowires were synthesized on germanium wafer via high-pressure chemical vapor deposition without the assistance of any catalysts. Magnetic measurements of FeGe2 nanowire arrays show strong anisotropic behavior: temperature dependent magnetization and field dependent magnetization and ac susceptibility show the mixture of ferromagnetism and antiferromagnetism. Nanowires integrated nanodevices with four electrodes were successfully fabricated using optimizd e-beam lithography process with e-beam dose correction and double layer geometry. The resistivity of isolated nanowires shows two resistive anomalies around 250 K and 200 K which correspond to abnormal resistivity changes at the magnetic transitions of the SDW state in bulk FeGe2, but are greatly enhanced by dimensionality effects under confinement. The ability to control and isolate these dimensionality effects in an antiferromagnetic system thus offers a tantalizing path forward in understanding and creating novel spin-dependent applications in the emerging fields of antiferromagnetic storage, resistive switching, and spintronics.