Magnetoelectronic properties of a ferrimagnetic semiconductor: The hybrid cupromanganiteCaCu3Mn4O

Abstract

The mixed manganite-cuprate CaCu3Mn4O12 is found, using density functional methods, to be a narrow gap (90 meV calculated) ferrimagnetic semiconductor. Cu (formally S= 1 2 ) antialigns with Mn (formally S = 3 2 ), and the net spin moment is 9 µB consistent with the formal spins. Holes have Cu dxy-O pσ (i.e. antibonding dpσ) character with spins aligned antiparallel to the net magnetization; electrons have the opposite spin and have mixed Cu dxy -Mn eg character. Thermally excited electrons and holes will each be fully spin polarized, but in opposite directions. The properties of this material are strongly tied to the distorted quadruple perovskite structure, which is closely related to the skutterudite structure. The observed resistivity, magnetoresistance, and magnetization are discussed in terms of our results.

Improving room temperature magnetoresistance in derivatives of ferrimagnetic CaCu3Mn4O12 perovskite

“…For NdCu 3 Mn 4 O 12 and TbCu 3 Mn 4 O 12 we find a metallic behavior up to 400 K. This fact can be explained through the band structure diagram proposed by Weth and Picket [3], where Mn e g levels are involved in the conduction band. When Mn 3+ is introduced, the compound is electron doped and the conduction band is progressively occupied leading to a metallic ground state.…”

Calculation of exchange constants of the Heisenberg model in plane-wave-based methods using the Green's function approach

“…On the other hand, this strongly suggests that the Hubbard correction, U , is not that important for the descriptions of the top of the valence and the bottom of the conduction bands. Indeed, many other Mn oxides can be described by the LSDA or GGA methods without account of any Hubbard correlations [56][57][58][59].…”

High-pressure preparation and characterization of new metastable oxides: the case of NdCu3Mn3MO12(M = Fe, Cr)

“…Among the few oxide systems that have been described to exhibit colossal magnetoresistance, simultaneously showing ferromagnetic (FM) and half-metallic character, the complex perovskite CaCu 3 Mn 4 O 12 [2][3][4][5] is particularly appealing. It exhibits a ferromagnetic (FM) Curie temperature significantly above room-temperature (RT), with T C = 355 K, and it shows good MR response at RT and low magnetic fields.…”