Spontaneous Relaxation of the Local4fMagnetization in CePd3

Diffuse neutron scattering on the intermediate valence compound Ce${\mathrm{Pd}}_3$ shows a quasielastic line with Lorentzian shape and very large, nearly temperature-independent width ($\frac{\Gamma }{2}\simeq 20$ meV). The intensity under this line has $4f$ form factor but the total cross section indicates only 0.5 $4f$ electron per formula unit. These observations are interpreted by spontaneous relaxation of the local $4f$ magnetization due to interconfiguration fluctuation between $4f^1$ and $4f^0$.