Negative magnetodielectric effect in CaCu₃Ti₄O ₁₂

Real part of complex relative dielectric value is relatively decreased as large as ∼ 5 % from 50 K to 200 K in CaCu₃Ti₄O ₁₂, by applying a 6-T static magnetic field. CaCu₃Ti ₄O₁₂ is thus implied primarily by the negative magnetodielectric effect, as a unified dielectric system in which 1-D finite dipole chains of B-site titanium ions, coexist with a collective of polaron-like 3d-electrons of A-site copper ions: the dipole chains are thermally activated for lattice ionic polarization above 50 K, and suppressed by the short-range hop of these quasi-particles, while their long-range movement are for bulk electronic polarization above 151 K.