Characterization of Magnetic Thin Films using the Magneto

Characterization of Magnetic Thin Films using the Magneto Optic Kerr Effect Nicholas J. Savino Lynchburg College Department of Physics

Magnetization "Hysteresis Loop and Magnetic Properties. " NDT Resource Center. NSF-ATE, n. d. Web.

Magneto Optic Kerr Effect (MOKE) Polarized Light Beam Change in Polarization Initial Polarization Sample Kerr, John. “XLIII. On Rotation of the Plane of Polarization by Reflection from the Pole of a Magnet. ” Philosophical Magazine, vol. 3, no. 19, ser. 5, 1877, pp. 321– 343. Davidson, Michael W. “John Kerr. ” Molecular Expressions: Science, Optics and You, National High Magnetic Field Laboratory, 13 Nov. 2015.

Thin Films Thin film of Ni and Fe. Pd (40 to 400 nm thick) Si wafer (0. 1 to 1 mm thick)

Laser Photodetector Polarizer Chopper Analyzer Electromagnet Crossed Polarizers

"Hysteresis Loop and Magnetic Properties. " NDT Resource Center. NSF-ATE, n. d. Web.

Data Hysteresis loop created by the Ni sample Hysteresis loop created by the Fe. Pd sample

Applications Biebel , Harald. “Brilliant Hard Drive Quality with Magnetic Field Sensors Made of Diamond. ” Phys. org, Fraunhofer Gesellschaft, 30 June 2016.

Future Work More samples • Cooling system allowing stronger magnetic field • Applying fields at different orientations • B B R. A. Lukaszew et al. / Applied Surface Science 219 (2003)

Acknowledgements Lukaszew Research Group at College of William and Mary, provided Fe. Pd capped with Au sample • Dr. William Roach, research advisor • New. Market Corporation, Virginia Foundation for Independent Colleges, Summer Undergraduate Science Research Fellowship •

Questions?

Lab. VIEW Block Diagram

Calibration 4000 3000 Magnetic field (G) 2000 1000 0 -4 -3 -2 -1 0 -1000 -2000 -3000 -4000 Current (A) 1 2 3 4

Methodology Lock-in and chopper set to 650 Hz • Polarizer oriented at approximately 320 degrees, analyzer oriented at approximately 170 degrees, nearly crossing the two • The samples tested were: – 100 nm Ni thin film sample on Si wafer (Ni) – 100 nm Ni thin film sample on 300 nm Si. O 2 on Si wafer (Ni on Si. O 2) – 40 nm Fe. Pd thin film sample capped with 5 nm Au (Fe. Pd capped with Au) •

Comparing Orientations Hysteresis loops created by Ni sample in orientation 1 in blue, orientation 2 in orange Hysteresis loops created by Ni (on Si. O 2)sample in orientation 2 in black, orientation 1 in red

Thank you!