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