Magnetism in nickel and synchrotron beam polarization studied by X-ray diffraction.
ABSTRACT The ratio of the magnetic to the charge form factors of nickel has been determined by white-beam X-ray diffraction. The measurements were made on the new UK magnetic scattering beamline (XMaS) on a dipole source at the ESRF. The data comprise the three (h,h,0) reflections (4,4,0), (6,6,0) and (8,8,0) and the seven high-order (h,0,0) reflections (6,0,0) to (18,0,0), which doubles the range of wavevectors compared to previous studies. The data have been analysed using Hartree-Fock free-ion wave functions and core electron polarization effects were included. The results support the interpretation of neutron data obtained at lower momentum transfer for the e(g) and t(2g) orbital occupancies. The polarization of the dipole source is deduced to vary from 99.88 to 99.83% between 5 and 15 keV, respectively. This high value makes it an extremely suitable source for studies of ferromagnetism.
Article: Magnetic diffraction of X-rays[Show abstract] [Hide abstract]
ABSTRACT: X-ray magnetic diffraction as a tool for studying magnetism is a new field that has developed as a result of the of the availability x-rays produced by synchrotron radiation sources. In non-resonant measurements the magnetic scattering is weak compared to the familiar charge scattering, but it is possible to use non-resonant measurements to measure spin and orbital scattering separately. Resonant measurements have demonstrated spectacular enhancements of the magnetic scattering and offer the prospect of studying weak magnetic phenomena.Radiation Physics and Chemistry 08/1999; 56(1):151-158. DOI:10.1016/S0969-806X(99)00277-7 · 1.19 Impact Factor
Article: Magnetic X-ray scattering[Show abstract] [Hide abstract]
ABSTRACT: Elastic and inelastic X-ray scattering methods can both be applied to the study of magnetic structure and magnetisation density. Their viability depends upon the highly polarised nature of the synchrotron radiation source as much as its inherent brightness and tuneability. Diffraction techniques have been used most effectively to study antiferromagnets; inelastic (Compton) scattering is complementary in that it is applicable to ferromagnets. Both methods have the capability to differentiate between the orbital and spin contributions to magnetisation. Examples of their application to studies of magnetism are given.Radiation Physics and Chemistry 08/1999; 56(1-2-56):85-99. DOI:10.1016/S0969-806X(99)00275-3 · 1.19 Impact Factor
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ABSTRACT: The magnetic spin structure factor of FeF2 has been directly determined from high energy magnetic x-ray diffraction at 115 keV photon energy. A pure spin moment of mu = 4.01(5)mu(B) was observed, which agrees very well with the spin moment of the free Fe2+ ion and differs significantly from values of the total magnetic moment obtained by other methods. The magnetic phase transition of FeF2 has been carefully investigated and values for the critical exponent of the order parameter obtained by other techniques have been confirmed.Physical Review Letters 05/2001; 86(14):3152-5. DOI:10.1103/PhysRevLett.86.3152 · 7.51 Impact Factor