Hyperfine-interaction parameters and magnetic phase antiferromagnet–ferromagnet transition in Ce(Fe1–xSix)2

Mössbauer spectroscopy study of Ce(Fe1–xSix)2 compounds with x = 0 and 0.07 was performed at different temperatures. Easy magnetization axis of the CeFe2 ferromagnet at 130 K was shown to be in the {110} plane and to deviate from the [001] axis by ∼10°. Upon cooling, the Ce(Fe0.93Si0.07)2 compound undergoes the ferromagnet–antiferromagnet phase transition in a temperature range of 120–125 K, which is accompanied by the reduction of the lattice symmetry. The Debye temperature of the Ce(Fe0.93Si0.07)2 compound was estimated using temperature dependences of the integral intensity of Mössbauer spectrum; it is TD ≈ 310 K. When analyzing the P(H) hyperfine field distributions P(H) derived from the Mössbauer spectra of Ce(Fe0.93Si0.07)2, it was found that in the cubic structure of this compound in the ferromagnetic state there occur local rhomboherdal distortions typical of the antiferromagnetic state.