New germanates RCrGeO5 (R=Nd–Er, Y): Synthesis, structure, and properties

摘要: Abstract The new complex germanates RCrGeO5 (R=Nd–Er, Y) have been synthesized and investigated by means of X-ray powder diffraction, electron microscopy, magnetic susceptibility specific heat measurements. All the compounds are isostructural crystallize in orthorhombic symmetry, space group Pbam, Z=4. crystal structure RCrGeO5, as refined using diffraction data, includes infinite chains built edge-sharing Cr+3O6 octahedra with two alternating Cr−Cr distances. combined into a three-dimensional framework Ge2O8 groups consisting edge-linked square pyramids oriented opposite directions. resulting contains pentagonal channels where rare-earth elements located. Thus, present examples RMn2O5-type show ordering Cr+3 Ge+4 cations. Electron well high-resolution microscopy confirm solution. Magnetic data for R=Nd, Sm, Eu qualitatively consistent presence isolated 3d (antiferromagnetically coupled cations) 4f (R+3) spin subsystems compounds. NdCrGeO5 undergoes long-range at 2.6 K, while SmCrGeO5 EuCrGeO5 do not any phase transitions down to 2 K.