High-Pressure Synthesis of a Novel PbFeO 3
- PDF / 822,751 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 15 Downloads / 170 Views
0988-QQ09-16
High-Pressure Synthesis of a Novel PbFeO3 Takeshi Tsuchiya1, Hiroyuki Saito1, Masashi Yoshida1, Tetsuhiro Katsumata1, Tomonori Ohba1, Yoshiyuki Inaguma1, Takao Tsurui2, and Masahiro Shikano3 1
Chemistry, Gakushuin University, 1-5-1, Mejiro, Toshima-ku, Tokyo, 171-8588, Japan
2
Institute for Materials Reserach, Tohoku Univesity, 2-1-1, Katahira, Aoba-ku, Sendai, 980-8577, Japan
3
Advanced Industrial Science and Technology, 1-8-31, Midorigaoka, Ikeda, Osaka, 563-8577, Japan
ABSTRACT A novel perovskite-type oxide PbFeO3 was successfully synthesized under a pressure as high as 7GPa, and the crystal structure, oxidation state, thermal stability, magnetic and dielectric properties were investigated. PbFeO3 possesses an orthorhombic perovskite unit cell and there is no phase transition between room temperature and 570 K. This compound decomposes into Pb2Fe2O5 in the vicinity of 740 K in air. According to XPS, it was found that this compound includes the Pb2+, Pb4+, and Fe3+ ions. INTRODUCTION Much attention has been recently paid to perovskite-type oxides (ABO3), which include Bi or Pb in the A-site and a transition metal in the B-site as they are candidates exhibiting ferromagnetic and ferroelectric properties at the same time, i.e., multiferroics. Among them, it has been reported that the Pb and 3d transition metal-containing perovskites, PbMO3 (M = Cr [1], V [2], Mn [3]) and PbFeO2F[4] were synthesized under high pressure. However, a perovskite-type oxide, PbFeO3 has never been reported in our knowledge. In this study we synthesized a novel perovskite PbFeO3 under high pressure and preliminarily investigated the crystal structure and physical properties. EXPERIMENTAL The starting materials were PbO (3N), PbO2 (3N), and Fe2O3 (4N). The mixed powder was sealed in a gold capsule (0.2 mm in thickness, 3.6 mm in inner diameter, and 3.4 mm in depth), which was placed in a NaCl sleeve. They were assembly set in a pyrophyllite block (13 × 13 ×
13 mm3) with a cylindrical graphite heater. The mixture was allowed to react in a TRY cubic multianvil-type high-pressure apparatus (NAMO 2001) at 6-7 GPa and 1273-1573 K for 30 min, and then was quenched to room temperature. The X-ray powder diffraction (XRD) data were collected with a Rigaku RINT 2100 diffractometer (graphite-monochromatized CuKα). The temperature dependence of lattice parameters of PbFeO3 was measured in the temperature range of 300 K to 570 K using a hand-made high-temperature cell on the same diffractometer. The determination of oxidation state of Pb and Fe was performed by the X-ray photoelectron spectroscopy (XPS) with a radiation source of MgKα. As the reference materials, LaFeO3, PbTiO3 prepared by a solid-state reaction, and a reagent PbO2 (3N) were used. The thermal stability of PbFeO3 was examined under air with a Bruker axs 2000S TG/DTA system. The sample was then placed in a Pt crucible, heated up to 973 K, and cooled to room temperature with a rate of 5 K/min. The magnetic susceptibility of PbFeO3 was measured with a Quantum Design MPM
Data Loading...
