Magnetic Speckle Images: A Cross-Correlation Study

POSTER

Abstract

Ferromagnetism has intrigued scientists since ancient times, and within the last few years, new methods have been developed to study the properties and behavior of thin ferromagnetic films. Soft X-Ray Resonant Magnetic Scattering (SXRMS) has been used to detect spatial and temporal variations in the microscopic magnetic domain of such films on the scale of $\sim$100nm. Coherent X-ray beams are projected through (or reflected off of) a sample, creating an interference speckle pattern in the reciprocal space, analogous to a Fourier Transform of the microscopic domain pattern. Speckles, or areas of high and low local intensity within these images are unique to the microscopic configuration of the magnetic domains. Thus, the magnetic memory, or extent to which a material will return to its original magnetic configuration, can be measured using quantitative cross-correlation of SXRMS images. In our analysis, we used Matlab to perform such cross-correlation procedures. We will discuss the methods of calculating the correlation coefficient ? between pairs of images (represented in matrix form), our optimization procedure, as well as data representing the cross-correlation of a Cobalt-Platinum sample measured at 20K. Inferences will be drawn regarding the magnetic memory of the sample.

Authors

  • Joe Nelson

    Brigham Young University, BYU

  • Shufang Su

    Iowa State University, Los Alamos National Laboratory, Lawrence Livermore National Laboratory, University of Arizona, Sandia National Laboratories, Physics Department, Texas Tech University, Lubbock, TX 79409-1051, Northwestern University, Texas Tech University, University of Utah Department of Physics, University of Toulouse-UPS, IRSAMC, Toulouse, France, University of Arizona, Department of Physics, National Institute of Advanced Industrial Science and Technology, Texas A\&M University, Midwest Proton Radiotherapy Institute, Birdville ISD, Universidad de Colima, Universidad de Buenos Aires, Brigham Young University, UT Atlington, MV Systems, Colorado State University, St. Petersburg Electrotechnical University, New Mexico State University, Texas State Univ., CAMD/LSU, Texas Christian University, Fort Worth, TX, North Side High School, Fort Worth, TX, Nitronex Corporation, Arizona State University, Angelo State University Department of Physics, Texas Tech University Deptarment of Electrical Engineering