Hope College Physics Department
Research Experiences for Undergraduates
|Project Title:||Electrodeposition and Characterization of Thin Films Created for Giant Magnetoresistance|
|Student Name:||Nicholas Wozniak|
|Student's Home Institution:||Hope College|
|Research Advisor:||Dr. Jennifer Hampton|
|Source of Support:||This material is based upon work supported by the National Science Foundation under NSF-REU Grant No. PHY-0452206, the Hope College Dean for the Natural and Applied Sciences Office, and the Hope College Department of Physics.|
The phenomenon of giant magnetoresistance (GMR) occurs when a non-magnetic
thin film is sandwiched between two magnetic films. In the presence of an external
magnetic field, the magnetic films align, allowing increased current flow.
Electrodeposition was used to create these films necessary for GMR. The magnetic
films were composed of nickel and iron while the non-magnetic films were composed
of copper. These films were deposited from sulfate solutions containing nickel
(100mM), iron (10mM), and copper (1mM) onto gold-plated silicon wafers. Particle
induced x-ray emission (PIXE) and atomic force microscopy (AFM) were used to
study how the deposition time (either 6 or 60 minutes) and deposition potential
(ranging from -500mV to -1200mV vs. Ag/AgCl) affect the composition and surface
roughness of the deposits. PIXE analysis showed that, at less negative potentials,
the deposit is dominated by copper, and as the potential becomes more negative,
the deposit has a greater nickel and iron concentration. PIXE also revealed
that the ratio of iron to total magnetic material changes with varying potential
and reaches a maximum value at -900mV. Analysis of RMS roughness from the AFM
data for varying length scales reveals the fractal nature of the deposits below
a characteristic length.
Publications and Presentations:
“Analysis of Electrodeposited Nickel-Iron Alloy Film Composition Using Particle-Induced X-ray Emission”, Alyssa A. Frey*, Nicholas R. Wozniak*, Timothy B. Nagi*, Matthew P. Keller*, J. Mark Lunderberg*, Graham F. Peaslee, Paul A. DeYoung, and Jennifer R. Hampton. Int. J. Electrochem, IJELC/604395, (2011).
"Electrodeposition and Characterization of Thin Films Created for Giant Magnetoresistance", Alyssa A. Frey, Nicholas R. Wozniak, and Jennifer R. Hampton, contributed poster, Celebration of Undergraduate Research & Creative Performance, Hope College, Holland, MI (April 9, 2010).
“An Electrochemical Cell for the Efficient Turn Around of Wafer Working Electrodes", Nicholas R. Wozniak, Alyssa A. Frey, Lucas W. Osterbur, Timothy S. Boman, and Jennifer R. Hampton, submitted to Rev. Sci. Instrum.
“Electrodeposition and Characterization of Thin Films Created for Giant Magnetoresistance", Alyssa A. Frey, Nicholas R. Wozniak, and Jennifer R. Hampton, contributed poster, Science and Engineering Summer Undergraduate Research Symposium, Notre Dame University, Notre Dame, IN, (July 31, 2009).