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ar X iv : 1 50 3 . 06 07 4 v 2 [ co nd-m at . s tr-e l ] 5 J un 2 01 5 Antiferromagnetism in EuCu
| Content Provider | Semantic Scholar |
|---|---|
| Author | Anand, Vijay Kumar Johnston, David C. |
| Copyright Year | 2015 |
| Abstract | Single crystals of EuCu2As2 and EuCu2Sb2 were grown from CuAs and CuSb self-flux, respectively. The crystallographic, magnetic, thermal and electronic transport properties of the single crystals were investigated by room-temperature x-ray diffraction (XRD), magnetic susceptibility χ versus temperature T , isothermal magnetization M versus magnetic field H , specific heat Cp(T ) and electrical resistivity ρ(T ) measurements. EuCu2As2 crystallizes in the body-centered tetragonal ThCr2Si2-type structure (space group I4/mmm), whereas EuCu2Sb2 crystallizes in the related primitive tetragonal CaBe2Ge2-type structure (space group P4/nmm). The energy-dispersive x-ray spectroscopy and XRD data for the EuCu2Sb2 crystals showed the presence of vacancies on the Cu sites, yielding the actual composition EuCu1.82Sb2. The ρ(T ) and Cp(T ) data reveal metallic character for both EuCu2As2 and EuCu1.82Sb2. Antiferromagnetic (AFM) ordering is indicated from the χ(T ), Cp(T ), and ρ(T ) data for both EuCu2As2 (TN = 17.5 K) and EuCu1.82Sb2 (TN = 5.1 K). In EuCu1.82Sb2, the ordered-state χ(T ) and M(H) data suggest either a collinear A-type AFM ordering of Eu spins S = 7/2 or a planar noncollinear AFM structure, with the ordered moments oriented in the tetragonal ab plane in either case. This ordered-moment orientation for the A-type AFM is consistent with calculations with magnetic dipole interactions. The anisotropic χ(T ) and isothermal M(H) data for EuCu2As2, also containing Eu +2 spins S = 7/2, strongly deviate from the predictions of molecular field theory for collinear AFM ordering and the AFM structure appears to be both noncollinear and noncoplanar. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.helmholtz-berlin.de/pubbin/oai_publication?ID=89986&VT=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |