강유전자성체 YMnO₃의 스토너 불안정성

Abstract

The Stoner criterion is very useful to find out the magnetic structure of a ferroelectromagnetic compound YMnO3. For the non-spin polarized case, the calculations shows that the Fermi level of YMnO3 is located in the region of a large peak of the density of states, which suggests a Stoner instability of non-magnetic state. The calculated IN(EF) of YMnO3 is 1.08, which implies that YMnO3 has a Stoner instability. Therefore YMnO3 favors a magnetic state rather than non-magnetic one. The calculation of electronic structure of YMnO3 shows that the Mn 3d orbitals and O 2p orbitals are located near the Fermi level and especially Mn 3d states play more important roles for the electromagnetic properties of this compound. The magnetic moment of this compound from local density approximation (LDA) calculation is 3.3 mu(B), which is very close with that of experimental results. In 3d transition metals the d electrons are itinerant, therefore the magnetic properties come from the 3d electron bands.