Magnetic response of Nd-doped nickel ferrites using magnetic Compton scattering and XPS measurements

Spin-polarized electron momentum densities of Nd-doped nickel ferrites (Ni1-xNdxFe2O4 where x = 0.12, 0.24) at 8 and 300K temperatures are presented. The measurements have been made using the magnetic Compton scattering set-up available at Spring-8, Japan. The site-specific spin moments which contribute to the formation of the total spin moment are deduced by decomposition of the magnetic Compton profile (MCP) into constituent profiles. An increase in the spin moment at Fe site and a reduction at Ni site with Nd doping, as revealed by MCP data, are explained on the basis of the cationic redistribution at octahedral and tetrahedral sites using x-ray photoelectron spectroscopy (XPS) analysis. The XPS measurements suggest the emergence of Fe2+ ions in Nd-doped samples to maintain the charge neutrality. It is found that the net spin moment at the Nd site is antiparallel to that at Ni and Fe sites. The orbital magnetic moment (deduced from the difference of magnetic Compton and total magnetization data) is also discussed. Copyright (C) EPLA, 2018