Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 49: Correlated Electrons: Low-dimensional Systems - Materials 4
TT 49.3: Vortrag
Freitag, 30. März 2012, 10:00–10:15, H 3005
The magnetic ground state of the frustrated spin chain linarite — •Britta Willenberg1,2, Markus Schäpers3, Kirrily Rule1, Stefan Süllow2, Manfred Reehuis1, Bachir Ouladdiaf4, Hanjo Ryll1, Klaus Kiefer1, and Anja Wolter3 — 1Helmholtz-Zentrum Berlin für Materialien und Energie, Germany — 2Institut für Physik der Kondensierten Materie, TU Braunschweig, Germany — 3Leibniz Institute for Solid State and Materials Research IFW, Dresden, Germany — 4Institute Laue-Langevin, Grenoble, France
The natural mineral linarite, PbCuSO4(OH)2, is found to be a frustrated one dimensional spin system. In the material CuO4 units form chains along the b axis, in which the Cu2+ ions are coupled ferromagnetically to the nearest neighbor with a coupling constant J1 ≈ 100 K and antiferromagnetically to the next nearest neighbor with J2 ≈ −36 K leading to a ratio J2 /J1 = -0.36. Due to a residual interchain couplings a magnetically ordered state is observed for temperatures below TN=2.8 K. We will present neutron diffraction results on the magnetically ordered ground state. The propagation vector indicates an incommensurate magnetic moment structure. The refinement of the neutron diffraction data shows that the structure is formed by an elliptical helical arrangement of moments. Furthermore, we will present magnetization measurements for temperatures down to 0.25 K in applied magnetic fields along the b axis indicating a very rich magnetic phase diagram, likely as a result of magnetic frustration.