Spin-resolved off-specular neutron scattering from magnetic domain walls using the polarized 3He gas spin filter

F. Radu, A. Vorobiev, J. Major, H. Humblot, K. Westerholt, H. Zabel

Research output: Contribution to journalConference article

21 Citations (Scopus)

Abstract

We report on the use of the polarized 3He gas filter and neutron resonant enhancement techniques for the measurement of spin-polarized diffuse neutron scattering due to ferromagnetic domains. A CoO/Co exchange biased bilayer was grown on a Ti/Cu/Al2O3 neutron resonator template. The system is cooled in an applied magnetic field of Ha = 2000 Oe through the Néel temperature of the antiferromagnet to 10 K where the applied magnetic field is swept as to measure the magnetic hysteresis loop. After the second magnetization reversal at the coercive field Hc2 = +230 Oe, the system is supposed to approach the original magnetic configuration. In order to prove that this is not the case for our exchange biased bilayer, we have measured four off-specular maps I+ +, I+-, I- +, I - - at Ha≈ + 370 Oe, where the Co magnetic spins were mostly reversed. They show a striking behavior in the total reflection region: while the nonspin-flip scattering exhibits no diffuse reflectivity, the spin-flip scattering shows strong diffuse scattering at incident angles which satisfy the resonance conditions. Moreover the spin-flip off-specular part of the reflectivity is asymmetric. The I - + intensity occurs at higher exit angles than the specularly reflected neutrons, and the I+ - intensity is shifted to lower angles. Their intensities are noticeably different and there is a splitting of the resonance positions for the up and down neutron spins (αn+≠αn-). Additionally, a strong influence of the stray fields from magnetic domains to the resonance splitting is observed.

Original languageEnglish
Pages (from-to)63-67
Number of pages5
JournalPhysica B: Condensed Matter
Volume335
Issue number1-4
DOIs
Publication statusPublished - Jul 2003
EventProceedings of the Fourth International Workshop on PNCMI 2002 - Julich, Germany
Duration: Sep 16 2002Sep 19 2002

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Keywords

  • Exchange bias
  • He neutron spin filter
  • Neutron resonator
  • Off-specular scattering
  • Spin-resolved neutron reflectivity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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