Extended magnetic exchange interactions in the high-temperature ferromagnet MnBi

Magnetic anisotropic effects and electronic correlations in MnBi ferromagnet

The electronic structure and numerous magnetic properties of MnBi magnetic systems are investigated using local spin density approximation (LSDA) with on-cite Coulomb correlations (LSDA+U ) included. We show that the inclusion of Coulomb correlations provides a much better description of equilibrium magnetic moments on Mn atoms as well as the magnetic anisotropy energy behavior with temperature...

Transport Spin Polarization of High-Curie Temperature MnBi Films

EXCHANGE INTERACTIONS AND MAGNETIC ANISOTROPY IN THE “Ni4” MAGNETIC MOLECULE

Magnetic properties of a tetrahedral “Ni4” molecule are discussed in terms of the Heisenberg model, with magnetic anisotropy terms included, and on the basis of first-principle calculations within the density functional theory. It is shown that the isotropic Heisenberg model does not provide an adequate description of magnetization at low temperatures; an inclusion of single-site anisotropy ter...

Suppression of the increase of high-temperature coercivity in MnBi thin films by Al interlayers

By tailoring the microcrystalline structure of MnBi films, using Al interlayers, a reduction of the high-temperature coercivity by a factor of 3 is achieved. The separation of Bi/Mn bilayers by Al interlayers acts as a diffusion barrier perpendicular to the surface. After annealing, the MnBi layers contain single-domain particles surrounded by an Al matrix exhibiting no significant increase of ...

Thermal stability of MnBi magnetic materials.

MnBi has attracted much attention in recent years due to its potential as a rare-earth-free permanent magnet material. It is unique because its coercivity increases with increasing temperature, which makes it a good hard phase material for exchange coupling nanocomposite magnets. MnBi phase is difficult to obtain, partly because the reaction between Mn and Bi is peritectic, and partly because M...