| 摘要 |
PROBLEM TO BE SOLVED: To provide a functional material having both of magnetism and ferroelectricity and capable of controlling ferroelectricity by a magnetic field or magnetism by an electric field, or the like; and to provide a method for producing the same. SOLUTION: The functional material is BiCoO<SB>3</SB>having a unit lattice of tetragonal crystal and a space group of P4mm. This tetragonal BiCoO<SB>3</SB>can be produced by mixing Bi<SB>2</SB>O<SB>3</SB>and a Co oxide so that the ratio of Bi to Co becomes 1:1 and reacting the resulting mixture at 1,000-1,300°C under pressure of 3-10 GPa. The tetragonal BiCoO<SB>3</SB>has such a structure that Bi<SP>3+</SP>ion 11 and Co<SP>3+</SP>ion 12, and O<SP>2-</SP>ion 13 are arranged with displacement in the c-axis direction, and shows ferroelectricity because an electric dipole moment is formed by such a displacement of the positive ion and the negative ion. Further, all spin number of Co<SP>3+</SP>ion 12 is 2 and thereby, the tetragonal BiCoO<SB>3</SB>has magnetism. Thus, the tetragonal BiCoO<SB>3</SB>has both of magnetism and ferroelectricity. COPYRIGHT: (C)2005,JPO&NCIPI
|
