| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that it has been extremely difficult to implement a millimeter wave band irreversible element appropriate for practical use since the irreversible element of 30 GHz to 300 GHz using a conventional magnetic material such as spinel ferrite or garnet ferrite requires a huge permanent magnet. <P>SOLUTION: The millimeter wave band irreversible element uses a magnetic material which is expressed by a chemical formula of M<SB>x</SB>Fe<SB>2-x</SB>O<SB>3</SB>, where 0<x<2 and M is made of at least one of In, Ga, Al, Sc, Cr, Sm, Yb, Ce, Ru, Rh, Ti, Co, Ni, Mn, Zn, Zr and Y, and has a crystal structure of a ε phase hematite. The magnetic material having the ε phase hematite as the main phase has a huge coercivity and an anisotropic magnetic field in an ambient temperature, thus making it possible not only to remarkably reduce the dimension of a magnetic circuit including a permanent magnet for the purpose of operating the element but also to totally eliminate the need of the magnetic circuit if it is optimally designed. <P>COPYRIGHT: (C)2009,JPO&INPIT |
