Berlin 2005 – scientific programme
Parts | Days | Selection | Search | Downloads | Help
TT: Tiefe Temperaturen
TT 3: Correlated Electrons - Heavy Fermions
TT 3.6: Talk
Friday, March 4, 2005, 11:30–11:45, TU H3027
Magnetic structure vs. crystallographic disorder in single crystalline UPt2Si2 — •S. Süllow1, A. Otop1, A. Loose2, J. Klenke2, R. Feyerherm2, R.W.A. Hendrikx3, and J.A. Mydosh3,4 — 1IFP, TU Braunschweig, Braunschweig, Germany — 2BENSC, HMI, Berlin, Germany — 3Leiden University, Leiden, The Netherlands — 4MPI-CPfS, Dresden, Germany
We present a detailed investigation of the crystallographic structure, lattice disorder and magnetic order of a single–crystal of the moderately mass–enhanced U intermetallic UPt2Si2. Utilizing the bright contrast between U, Pt and Si in neutron scattering, we establish the lattice symmetry to be P4/nmm (CaBe2Ge2-lattice). Moreover, the observation of an anomalously large thermal displacement factor U11/U22 for the Pt(2) and Si(2) sites at low temperatures indicates frozen–in disorder on these sites. The material undergoes an antiferromagnetic transition below TN = 32.1 K, with ferromagnetically coupled a – b –planes and an antiferromagnetic stacking along the c axis. In addition, as result of the crystallographic disorder we observe magnetic clusters up to Tirr = 34 K. The existence of the clusters explains the previously observed anomalous antiferromagnetic domain pinning in the compound [1]. Moreover, the disorder bears relevance to the electronic transport properties of the compound, which are commonly metallic along the a axis, but disorder dominated in c direction.
[1] A. Otop et al., J. Appl. Phys. 95 (2004) 6702