Local structure of multiferroicTbMn2O5: Evidence for an anomalous Tb-O distribution

Abstract

The temperature dependent local structure of TbMn 2 O 5 was determined by x-ray absorption spectroscopy.An anomalous Tb-O distribution is found. At high temperature it is broad but resolves into two distinct peaks below ~180 K. The distributions sharpen below the Tb magnetic ordering temperature (~10 K). The distortions in the Tb-O distribution, away from the Pbam structure, are consistent with rotations of the MnO x polyhedra about the c-axis and suggest that Tb-O bond polarization may play a significant role in the observed ferroelectric properties of this system.

Local structure of multiferroic RMn2O5: Important role of the R site

“…The data are consistent with rotations of the polyhedra about the c-axis generated by bucking at the ''hinges'' connecting them [15].…”

“…We combine previous temperature-dependent data on the Tb system [15] with recent field-dependent data on the Dy system. In Fig.…”

“…2 (c). Detailed multiple shell analysis was conducted for the Tb-O distribution [15]. Below $180 K the Tb-O distribution is composed of well-resolved components which sharpen in intensity at the Tb ordering temperature.…”

“…Magnetic field measurements were conducted at 3 K. The reduction of the X-ray absorption finestructure (XAFS) data was performed using standard procedures and follows the details of Ref. [15].…”

Local structure of thermoelectricCa3Co4O9

“…Data analysis was carried out as in Ref. 17. Representative absorption fine-structure data at 270 K are shown in Fig.…”