Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 25: Correlated Electrons - Poster Session
TT 25.75: Poster
Mittwoch, 29. März 2006, 14:30–18:30, P1
Crossover from Ferro- to Antiferromagnetism in the Layered Kondo Systems CeTPO (T=Ru, Os) — •Cornelius Krellner1, Nagesh S. Kini2, and Christoph Geibel1 — 1Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany — 2Department of Applied Chemistry, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima 739-8527, Japan
Intermetallic Kondo lattice systems have attracted considerable attention in the last decades. While their exist many Ce-based compounds showing antiferromagnetical ground states, only very few systems are known with ferromagnetic order. On the way to find new Ce-based Kondo lattices close to a ferromagnetic quantum phase transition, the CeTPO (T=transition metal) compound series attracted our interest, because of the rather unusual crystal structure with alternating layers of TP4 and OCe4 tetrahedra. In this contribution we will present the first investigation of the physical properties of CeTPO (T=Ru, Os) crystallizing with the tetragonal ZrCuSiAs type structure (P4/nmm). Measurements of the magnetic susceptibility reveal that in both compounds Cerium is in a trivalent state. A pronounced decrease of the resistivity below 50 K indicates the coherence effects of a Kondo scale of order TK=10 K. But whereas CeRuPO shows a ferromagnetic transition at 15 K both in temperature dependent susceptibility and specific heat, the isoelectronic CeOsPO becomes antiferromagnetic below 4.4 K. The possible origin of these effects will be discussed.