La-Doping and External Pressure Effects on the Crystal Structure of Layered Perovskite-Like Manganate Ca3Mn2O7

✍ Scribed by Zhu, J.L. ;Yu, R.C. ;Li, F.Y. ;Jin, C.Q.

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 133 KB
• Volume: 194
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/1521-396x(200211)194:1<159::aid-pssa159>3.0.co;2-9

✦ Synopsis

The effects of La-doping and external pressure on the crystal structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 have been investigated by substituting La 3+ for Ca 2+ in Ca 3 Mn 2 O 7 and in situ high pressure energy dispersive X-ray diffraction measurements on Ca 3 Mn 2 O 7 , respectively. With the increase of La 3+ content in compounds with nominal compositions, La 2--2x Ca 1+2x Mn 2 O 7 (x = 1.0-0.5), single-phase compounds with a tetragonal structure are formed only in the range x = 1.0-0.6 and the lattice parameter a increases with increasing La-doping level while c decreases. Similarly, with the increase of external pressure in the range 0-1.3 GPa, the lattice parameter a of the layered perovskite manganate Ca 3 Mn 2 O 7 increases while c decreases, and the structure of Ca 3 Mn 2 O 7 undergoes a phase transition from a tetragonal to a orthorhombic structure at about 1.3 GPa. The La-doping and external pressures have the same effect on the lattice structure of the layered perovskite manganate Ca 3 Mn 2 O 7 .