anomalous hall effect in copper-nickel thin films · anomalous hall effect in copper-nickel thin...
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Kenneth Galazka, Devon Brewer Advisors: Dr. Sunil Labroo, Dr. James Michels
Department of Physics & Astronomy - SUNY Oneonta
Anomalous Hall Effect in Copper-Nickel Thin Films
Abstract
• Measurement Hall Resistance vs Magnetic Field at constant current shows
hysteresis, which is consistent with the Anomalous Hall Effect in Magnetic Films [1]
• Primary focus on Extraordinary Hall Effect
• Various concentrations of Ni in Cu
• Consideration of magnetization of Ni on Hall Resistance
• Research is ongoing
[1] A. Gerber et al. Journal of Magnetism and Magnetic Materials 242-245 (2002) 90-97.
Experimental Setup
Sample Specifications
• Samples measured: 100 at.%, 25 at.%, and 20 at.% Ni in Cu • Estimated film thicknesses of 2300-2500 Å • Atomic fractions prepared using arc melting and thermal evaporation
Data and Observations
References: [1] Extraordinary Hall effect in magnetic films, Gerber et. al, Journal of Magnetism
& Magnetic Materials, Vol. 242-245 (2002) p.90-97.
[2] Extraordinary Hall Effect in Dilute Magnetic Thin Films, Matthew Cohen, Sunil
Labroo & Jim Michels, Student Research & Creative Activity Day, April 18, 2012.
Also presented at the American Physical Society (NY Section) meeting at
Binghamton University, April 20, 2012.
[3] Observation of Extraordinary Hall Effect in Cu-Ni Thin Films, Luke D’Imperio
& Sunil Labroo, Life of the Mind Faculty Research Day, October, 2010.
Summary of Results
Future Considerations
A Special Thanks to:
Dr. Sunil Labroo, Dr. Allen Anderson, Physics Department Binghamton University, and Diana Moseman (TLTC)
Van der Pauw Method
• Contacts should be as small as possible on corners of sample • Constant current across 1-3, measure voltage across 2-4 • Then, send constant current across 2-4, measure voltage across 1-3 • Average V24 and V13 to increase accuracy
• Anomalous Hall Effect of 100% Ni sample • Observed unusual Hysteresis behavior • Hysteresis effect seen over a ± 600 mT range • Explored performance enhancement methods -Thinner wires for more sturdy contacts -Van der Pauw Method -Averaging V24 and V13
• Samples of pure Cu, 1%, and 5% in Cu • Determine and compare Hall Resistance saturation levels • Assess RH saturation vs. Ni concentration • Does the saturation level scale with Ni concentration? • Does VH increase with decreasing film thickness?
1
2
4
3
V Sample Switch 1 Switch 2
Keithley 2400
Constant Current
Source
Keithley 2182
Nanovoltmeter
0.06935
0.0694
0.06945
0.0695
0.06955
0.0696
0.06965
0.0697
0.06975
0.0698
-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8
25 at.% Ni Sample (4/4/13)
Increasing Pos. Field
Decreasing Pos. Field
Increasing Neg. Field
Decreasing Neg. Field
0.65
0.7
0.75
0.8
0.85
0.9
0.95
-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8
100 at.% Ni Sample (4/11/13)
Increasing Pos. Field
Decreasing Pos. Field
Increasing Neg. Field
Decreasing Neg. Field
0.02525
0.0253
0.02535
0.0254
0.02545
0.0255
0.02555
0.0256
0.02565
0.0257
0.02575
-0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8
10 at.% Ni Sample (4/16/13)
Increasing Pos. Field
Decreasing Pos. Field
Increasing Neg. Field