Magnetic properties and crystallographic properties of Cu_(1-x)Ge_(1-y)Fe_(x+y)O₃ system were studied by using x-ray diffraction, superconducting quantum interference device (SQUID) and Mossbauer spectroscopy. All the samples have orthorhombic struc...
Magnetic properties and crystallographic properties of Cu_(1-x)Ge_(1-y)Fe_(x+y)O₃ system were studied by using x-ray diffraction, superconducting quantum interference device (SQUID) and Mossbauer spectroscopy. All the samples have orthorhombic structure and the lattice constants some decreased as the substituted iron contents increasing. The spin-Peierls (SP) transition temperatures of our samples are about 12.5 K and these temperatures lowered as increasing substituted iron contents. The Mossbauer spectra consisted with two Zeeman sextets and one doublet due to Fe³+ ions. The jump up of magnetic hyperfine field of 2nd Zeeman sextet and the increasing of the values of quadrapole splitting and isomer shift of doublet below SP transition temperature could be interpreted with the variation of the superexchange interaction, the symmetry of lattice sites and the covalency of bonds due to the atomic displacements.