Polarized neutron diffraction at a spallation source for magnetic studies

A. Pramanick, V. Lauter, X. L. Wang, K. An, H. Ambaye, R. J. Goyette, J. Yi, Z. Gai, A. D. Stoica

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The availability of high-power spallation neutron sources, along with advances in the development of coupled moderators and neutron polarizers, has made it possible to use polarized neutrons on time-of-flight diffractometers for in situ studies of phenomena contributing to field-induced magnetization of a material. Different electronic and structural phenomena that contribute to the overall magnetization of a material can be studied and clearly identified with polarized neutron diffraction measurements. This article reports the first results from polarized neutron diffraction experiments on a time-of-flight instrument at a spallation source. Magnetic field-induced rotation of electron spins in an Ni-Mn-Ga single crystal was measured with polarized neutron diffraction at the MAGICS reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. The difference in intensities measured with spin-up and spin-down polarized neutrons is proportional to the field-induced magnetization of the crystal. The polarized neutron measurements indicate that the magnetic form factor for the 3d electrons of Mn in Ni-Mn-Ga is lower than the value reported earlier for an ideal spherical symmetry of electronic distribution. Future experiments for studying field-induced magnetization in materials following the current methodology are outlined.

Original languageEnglish
Pages (from-to)1024-1029
Number of pages6
JournalJournal of Applied Crystallography
Volume45
Issue number5
DOIs
StatePublished - Oct 2012

Keywords

  • ferromagnetic shape memory alloys
  • magnetization
  • polarized neutron diffraction

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