Citation

Lalić MV, Mestnik-Filho J, Carbonari AW, Saxena RN. J. Phys. Condens. Matter 2004; 16(37): 6685-6693.

Copyright

(Copyright © 2004, IOP Publishing)

DOI

10.1088/0953-8984/16/37/005

PMID

unavailable

Abstract

The low-temperature magnetic properties of the Ce atoms in the intermetallic compounds CeMn2Ge2 and CeMn 2Si2 were studied. Previous neutron scattering measurements did not detect an ordered moment at Ce atoms in either compound despite the fact that they are surrounded by the Mn moments ordered ferromagnetically in the CeMn2Ge2 and antiferromagnetically in the CeMn2Si2. Contrasting with this result, a recent measurement performed with the time differential perturbed angular correlation (TDPAC) technique showed the presence of a pronounced magnetic hyperfine field (MHF) at Ce sites in the CeMn2Ge2 compound and no MHF in CeMn2Si2. The absence of the Ce magnetic moment and MHF in the suicide can be understood in terms of too weak a Ce-Ce magnetic interaction while in the germanide the TDPAC result suggests that some magnetic ordering of Ce atoms may occur. Aiming to understand the effects which result in the quenching of the Ce 4f moment in both cases, we performed first-principles band-structure calculations for both systems, using the full potential linear augmented plane wave method. It is shown that the magnetism of the Ce sublattice has fundamentally different nature in CeMn2Si 2 and CeMn2Ge2. While the Ce atoms are intrinsically nonmagnetic in the suicide, having a zero magnetic moment with both spin and orbital contributions identically zero, they display magnetic properties in the CeMn2Ge2 since their very small total moment is composed of finite spin and orbital components which almost cancel each other accidentally.

Language: en

Keywords

Perturbation techniques; Intermetallics; Low temperature effects; Magnetization; Neutron scattering; Magnetic properties; Band structure; Magnetic moments; Atoms; Cerium compounds; Low temperature magnetic properties; Magnetic fields; Magnetic hyperfine fields (MHF); Magnetism; Plane wave method; Time differential perturbed angular correlation (TDPAC)