¹⁴⁰Ce (←¹⁴⁰La) Time-Differential Perturbed Angular Correlation Study of CeRu₂Ge₂

Abstract

The hyperfine interaction at ¹⁴⁰Ce nucleus in CeRu₂Ge₂ has been investigated, using the ¹⁴⁰Ce Time-Differential Perturbed Angular Correlation (TDPAC) method. ¹⁴⁰Cs ions, which are fission products from ²³⁵U, have been implanted into a single crystal of CeRu₂Ge₂ at room temperature. ¹⁴⁰Cs decays to ¹⁴⁰Ce 4+ intermediate state through ¹⁴⁰Ba with the life-time of 12.752 days and ¹⁴⁰La with a life-time of 1.6781 days. TDPAC spectrum at 4.2 K clearly shows the existence of the magnetic perturbation, which is absent at room temperature. Larmor frequency observed at 4.2 K is 1.32(1) Grad/s corresponding to the hyperfine magnetic field of 24.2(2) T at ¹⁴⁰Ce nucleus. Magnetization measurements of CeRu₂Ge₂ performed by using the SQUID magnetometer revealed the magnetic moment of 1.848 μ_B which indicates that the hyperfine coupling constant of Ce is 13.1(3) T/μ_B.