title: Evidence for differentiation in the iron-helicoidal chain in GdFe3(BO3)4.
abstract: A single-crystal X-ray structure study of gadolinium triiron tetraborate, GdFe3(BO3)4, at room temperature and at 90 K is reported. At room temperature GdFe3(BO3)4 crystallizes in a trigonal space group, R32 (No. 155), the same as found for other members of the iron borate family RFe3(BO3)4. At 90 K the structure of GdFe3(BO3)4 transforms to the space group P3(1)21 (No. 152). The low-temperature structure determination gives new insight into the weakly first-order structural phase transition at 156 K and into the related Raman phonon anomalies. The presence of two inequivalent iron chains in the low-temperature structure provides a new perspective on the interpretation of the low-temperature magnetic properties.
authors.affiliation: Material Science Center, University of Groningen, 9747 AG Groningen, The Netherlands.
authors.forename: S A
authors.initials: SA
authors.lastname: Klimin
authors.forename: D
authors.initials: D
authors.lastname: Fausti
authors.forename: A
authors.initials: A
authors.lastname: Meetsma
authors.forename: L N
authors.initials: LN
authors.lastname: Bezmaternykh
authors.forename: P H M
authors.initials: PH
authors.lastname: van Loosdrecht
authors.forename: T T M
authors.initials: TT
authors.lastname: Palstra
mesh_terms: D001881:Borates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005682:Gadolinium / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D010100:Oxygen / Q000737:chemistry; D044367:Phase Transition; D012984:Software; D013059:Spectrum Analysis, Raman; D013696:Temperature
chemical_list: D001881:Borates; D008024:Ligands; C506608:gadolinium triiron tetraborate; D005682:Gadolinium; D007501:Iron; D010100:Oxygen