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

Resumo

Mössbauer spectroscopy study of Ce(Fe_1–xSi_x)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(Fe_0.93Si_0.07)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(Fe_0.93Si_0.07)₂ compound was estimated using temperature dependences of the integral intensity of Mössbauer spectrum; it is T_D ≈ 310 K. When analyzing the P(H) hyperfine field distributions P(H) derived from the Mössbauer spectra of Ce(Fe_0.93Si_0.07)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.