| Summary: | 博士 === 國立中山大學 === 電機工程研究所 === 84 === The minium room-temperature resistivity for La-Mn-codoped
BaTiO3 with A.S.T. occurs at [La]-5/3[Mn]=0.35 mol%. Most
of Mn are in the bulk regions, existing as divalent ions.
Theas trivelent ions, should be at the grain boundaries.
Thee resistivity of La-doped BaTiO3 increases with the
increased Mn even La and Mn are in the balenced situation. Mn
exhibits a inhibition effect which results in the increase of
grainus, the semiconductivity of La-doped BaTiO3 is decreased
by Mn For La-Mn-codoped BaTiO3 without A.S.T., the relationship
of La Mn which results in the minimum room-temperature
resistivity is [Mn]=0.275 mol%. Mn ions, segregated at the
grain boundaries, acceptor levels to reduse the electron
generation velocity. content increases, the negative
temperature coefficient (NTC) BaTiO3 positive temperature
resistivity (PTCR) below Tc will be The NTC effect of BaTiO3
PTCR could be slightly increased by soaking time or slowing
cooling rate. The slope of PTCR effect is with the increased Mn
content. However, the maximum order of PTCR stsat [Mn] is
about0.06~0.09mol%.
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