Neutron scattering and thermal studies of the Ni-incorporated CeSbNix system
PhysRevB_62_12181.pdf 158 KB
Adroja, D. T.
Armitage, J. G. M.
Riedi, P. C.
Jung, M. H.
Neutron scattering, thermal expansion, and magnetostriction measurements have been carried out on the cubic compounds CeSbNix (x=0-0.4). Inelastic neutron scattering studies show a well-defined crystal field (CF) excitation at 4.06 (±0.04) meV and 5.02(±0.05) meV in x=0.08 and 0.15, respectively. The crystal field splitting increases with x compared with the parent compound CeSb (3.19 meV) in spite of the lattice parameter increasing with Ni incorporation. The implication is that the increase in the CF splitting in x=0.08 and 0.15 is due to a collapse of the p-f mixing between the Sb 5p holes and the localized Ce 4f electrons. The analysis of inelastic spectra of x=0.15 shows that the ground state is a doublet (Γ7), which explains the temperature-dependent behavior of the magnetic susceptibility. Thermal expansion shows a dramatic change in behavior with Ni composition. The thermal expansion coefficient exhibits a first-order transition at 15.4 K in CeSb, which disappears for Ni composition as low as x=0.035, as well as in an applied field of 8 T. A large magnetostriction has been observed in CeSb in the magnetic-ordered state as well as in the paramagnetic state. The absolute values of the magnetostriction are reduced considerably in the Ni-incorporated alloys. The volume magnetostriction of x= 0.15 alloy exhibits a scaling behavior in the paramagnetic state from which we have estimated the product of the magnetovolume coupling constant and the isothermal compressibility.
Physical Review B - Condensed Matter and Materials Physics
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