Magnetometry of Individual Polycrystalline Ferromagnetic Nanowires.
Ferromagnetic nanowires are finding use as untethered sensors and actuators for probing micro- and nanoscale biophysical phenomena, such as for localized sensing and application of forces and torques on biological samples, for tissue heating through magnetic hyperthermia, and for microrheology. Quantifying the magnetic properties of individual isolated nanowires is crucial for such applications. Dynamic cantilever magnetometry is used to measure the magnetic properties of individual sub-500 nm diameter polycrystalline nanowires of Ni and Ni80Co20fabricated by template-assisted electrochemical deposition. The values are compared with bulk, ensemble measurements when the nanowires are still embedded within their growth matrix. It is found that single-particle and ensemble measurements of nanowires yield significantly different results that reflect inter-nanowire interactions and chemical modifications of the sample during the release process from the growth matrix. The results highlight the importance of performing single-particle characterization for objects that will be used as individual magnetic nanoactuators or nanosensors in biomedical applications.
Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland.
Naveen
N
Shamsudhin
Department of Physics, ETH Zurich, Zurich, 8092, Switzerland.
Ye
Y
Tao
Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, 08193, Spain.
Jordi
J
Sort
Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland.
Bumjin
B
Jang
Department of Physics, ETH Zurich, Zurich, 8092, Switzerland.
Christian L
CL
Degen
Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland.
Bradley J
BJ
Nelson
Multi-Scale Robotics Laboratory, ETH Zurich, Zurich, 8092, Switzerland.
Salvador
S
Pané
D060306:Magnetometry / Q000379:methods*; D059346:Magnets / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires / Q000737:chemistry*
cantilever magnetometry; electron backscattered diffraction; ferromagnetic nanowires; nanorobotics