Ab initio study on the magnetostructural properties of MnAs
File Type:
PDFItem Type:
Journal ArticleDate:
2006Access:
openAccessCitation:
I. Rungger and S. Sanvito, Ab initio study on the magnetostructural properties of MnAs, Phys. Rev. B, 74, 2006, 024429Download Item:
Abstract:
The magnetic and structural properties of MnAs are studied with
ab initio
methods and by mapping total
energies onto a Heisenberg model. The stability of the different phases is found to depend mainly on the
volume and on the amount of magnetic order, confirming previous experimental findings and phenomenologi-
cal models. It is generally found that for large lattice constants the ferromagnetic state is favored, whereas for
small lattice constants different antiferromagnetic states can be stabilized. In the ferromagnetic state the
structure with minimal energy is always hexagonal, whereas it becomes orthorhombically distorted if there is
an antiferromagnetic alignment of the magnetic moments in the hexagonal plane. For the paramagnetic state
the stable cell is found to be orthorhombic up to a critical lattice constant of about 3.7 Å, above which it
remains hexagonal. This leads to the second-order structural phase transition between paramagnetic states at
about 400 K, where the lattice parameter increases above this critical value with rising temperature due to the
thermal expansion. We also evaluate the magnetic susceptibility as a function of temperature, from which a
semiquantitative description of the MnAs phase diagram emerges
Author's Homepage:
http://people.tcd.ie/sanvitosDescription:
PUBLISHED14 pgs
Author: SANVITO, STEFANO; RUNGGER, IVAN
Type of material:
Journal ArticleCollections
Series/Report no:
Phys. Rev. B74
Availability:
Full text availableKeywords:
structural properties of MnAsDOI:
http://dx.doi.org/10.1103/PhysRevB.74.024429Metadata
Show full item recordLicences: