Berlin 2005 – scientific programme

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.124: Poster

Monday, March 7, 2005, 14:00–18:00, Poster TU C

Magnetic structure of Tb₂PdSi₃: Investigation of long- and short- range magnetic order in external magnetic fields — •Matthias Frontzek¹, Andreas Kreyssig¹, Mathias Doerr¹, Jens-Uwe Hoffmann², and Michael Loewenhaupt¹ — ¹TU Dresden, Institut für Festkörperphysik, D-01062 Dresden — ²Hahn-Meitner-Institut, BENSC, Glienicker Straße 100, D-14109 Berlin

Tb₂PdSi₃, crystallizing in an AlB₂ derived hexagonal structure (space group P 6/mmm) shows a very complex magnetic behavior due to low-dimensional magnetism as well as spin-glass like properties. The hexagonal structure allows the possibility of a 2-dimensional geometrical frustration which might be the cause of the observed spin-glass like behavior.

Tb₂PdSi₃ orders antiferromagnetically at T_N = 23 K and undergoes a spin-glass like transition at T₂ = 9 K. For the zero field long-range antiferromagnetic structure we determine a propagation vector (1/2, 1/2, 1/16) at T = 2 K. Additionally we observe intensity due to antiferromagnetic short-range order (SRO) with a correlation length of about 30 Å. The observed antiferromagnetic SRO is probably linked to the spin-glass like transition. The magnetic behaviour of Tb₂PdSi₃ investigated with ac susceptibility and magnetisation delivered ambiguous results and left open several questions. Using neutron diffraction in external magnetic fields we studied the microscopic cause of the hysteretic behaviour and the coexistence of different long-range and short range ordered magnetic phases up to a field of µ₀H = 6.5 T. In our contribution we will present and discuss the results.