Temperature dependence of the hyperfine magnetic field in SrRuO3 measured hy the Ru-99 Mossbauer effect

The hyperfine magnetic held in the ferromagnetic metal, SrRuO3, has been me asured from 4.2 to 166.3 K by the Ru-99 Mossbauer effect. The hyperfine fie ld at 4.2 K is determined to be 33.0(0.4) T with an isomer shift of -0.33(. 02) mm/s. The Curie temperature is determined 162(2) K for a polycrystallin e sample. This is consistent with the determination by Cao et al. [Phys. Re v. B 56, 321 (1997)1 of T-C= 165 K for a single crystal. The Mossbauer effe ct full width at half maximum linewidth at 166.3(0.1) K, above the Curie te mperature, is as narrow as the natural linewidth of Mossbauer effect state without broadening due to regions of short range ferromagnetic order. This indicates that the compound at this temperature is in a paramagnetic state.