Magnetization and Hyperfine Structure of 57Fe in CsFeF3

Abstract
Magnetic measurements and Mössbauer effect (ME) studies of 57Fe in CsFeF3 are reported. The compound is hexagonal at room temperature, but undergoes a crystallographic transformation at 83°K to a structure with lower symmetry. Magnetization data show a spontaneous magnetization appearing at TC=62°K, with a saturation magnetization at low temperatures of 1.72 μB per formula unit. In the magnetic state ME yields well resolved hfs corresponding to the two magnetically inequivalent iron sites. At 4.2°K the following hyperfine structure parameters have been obtained: Heff(A)=318 kOe, Heff(B)=274 kOe; Q.S. (A)=−2.85 mm/sec, and Q.S. (B)=−1.9 mm/sec, with the axes of the EFG tensors at 40° to the direction of the magnetic moments.