Antiferromagnetism in EuNiGe3

TitleAntiferromagnetism in EuNiGe3
Publication TypeJournal Article
Year of Publication2013
AuthorsGoetsch RJ, Anand VK, Johnston DC
Journal TitlePhysical Review B
Volume87
Pages064406
Date Published02
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000314759200001
Keywordscrystal, lu, magnetic-structure, nd, ni, series, SM
Abstract

The synthesis and crystallographic and physical properties of polycrystalline EuNiGe3 are reported. EuNiGe3 crystallizes in the noncentrosymmetric body-centered tetragonal BaNiSn3-type structure (space group I4mm), in agreement with previous reports, with the Eu atoms at the corners and body center of the unit cell. The physical property data consistently demonstrate that this is a metallic system in which Eu spins S = 7/2 order antiferromagnetically at a temperature T-N = 13.6 K. Magnetic susceptibility chi data for T > T-N indicate that the Eu atoms have spin 7/2 with g = 2, that the Ni atoms are nonmagnetic, and that the dominant interactions between the Eu spins are ferromagnetic. Thus we propose that EuNiGe3 has a collinear A-type antiferromagnetic structure, with the Eu ordered moments in the ab plane aligned ferromagnetically and with the moments in adjacent planes along the c axis aligned antiferromagnetically. A fit of chi(T <= T-N) by our molecular field theory is consistent with a collinear magnetic structure. Electrical resistivity rho data from T-N to 350 K are fitted by the Bloch-Gruneisen model for electron-phonon scattering, yielding a Debye temperature of 265(2) K. Astrong decrease in. occurs below T-N due to loss of spin-disorder scattering. Heat capacity data at 25 K <= T <= 300 K are fitted by the Debye model, yielding the same Debye temperature 268(2) K as found from rho(T). The extracted magnetic heat capacity is consistent with S = 7/2 and shows that significant short-range dynamical spin correlations occur above T-N. The magnetic entropy at T-N = 13.6 K is 83% of the expected asymptotic high-T value, with the remainder recovered by 30 K. DOI: 10.1103/PhysRevB.87.064406

URL<Go to ISI>://WOS:000314759200001
DOI10.1103/PhysRevB.87.064406