TY  - JOUR
AU  - Bauer, A.
AU  - Regnat, A.
AU  - Blum, C. G. F.
AU  - Gottlieb-Schönmeyer, S.
AU  - Pedersen, B.
AU  - Meven, M.
AU  - Wurmehl, S.
AU  - Kuneš, J.
AU  - Pfleiderer, C.
TI  - Low-temperature properties of single-crystal CrB$_{2}$
JO  - Physical review / B
VL  - 90
IS  - 6
SN  - 1098-0121
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2015-00762
SP  - 064414
PY  - 2014
AB  - We report the low-temperature properties of 11B enriched single-crystal CrB2 as prepared from high purity Cr and B powder by a solid-state reaction and optical float-zoning. The electrical resistivity, ρxx, Hall effect, ρxy, and specific heat, C, are characteristic of an exchange-enhanced Fermi liquid ground state, which develops a slightly anisotropic spin gap Δ≈220~K below TN=88~K. This observation is corroborated by the absence of a Curie dependence in the magnetisation for T→ 0 reported in the literature. Comparison of C with dxx=dT , where we infer lattice contributions from measurements of VB2, reveals strong antiferromagnetic spin fluctuations with a characteristic spin fluctuation temperature Tsf≈257~K in the paramagnetic state, followed by a pronounced second order mean-field transition at TN, and unusual excitations around ≈TN/2. The pronounced anisotropy of ρxx above TN is characteristic of an easy-plane anisotropy of the spin fluctuations consistent with the magnetisation. The ratio of the Curie-Weiss to the Neel temperatures, f=−ΘCW/TN≈ 8.5, inferred from the magnetisation, implies strong geometric frustration. All physical properties are remarkably invariant under applied magnetic fields up to 14~T, the highest field studied. In contrast to earlier suggestions of local moment magnetism our study identifies CrB2 as a weak itinerant antiferromagnet par excellence with strong geometric frustration.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000341104600004
DO  - DOI:10.1103/PhysRevB.90.064414
UR  - https://juser.fz-juelich.de/record/186690
ER  -