Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 50: Poster Session: Correlated Electrons 2

TT 50.23: Poster

Mittwoch, 3. April 2019, 15:00–18:30, Poster D

The complex magnetic phase diagram of clinoatacamite — •Jannis Willwater¹, Jan Lennart Winter¹, Leonie Heinze¹, Dirk Menzel¹, Stefan Süllow¹, Manfred Reehuis², Fabiano Yokaichiya², Ralf Feyerherm², Harald O. Jeschke^3,4, and Roser Valentí⁴ — ¹IPKM, TU Braunschweig, Braunschweig, Germany — ²HZB, Berlin, Germany — ³Okayama University, Okayama, Japan — ⁴Institut für Theoretische Physik, Goethe-Universität Frankfurt, Frankfurt, Germany

The natural mineral clinoatacamite (Cu₂Cl(OH)₃) has been discussed as geometrically frustrated magnet. The Cu²⁺ ions form a system of kagome layers with an antiferromagnetic in-plane coupling. This 2-dimensional geometrical frustration may lead to exotic quantum states at low temperatures.

Here, we present an extensive study using different experimental methods that reveal a complex magnetic phase diagram of the material at low temperatures. The measurements of the specific heat, magnetic susceptibility and magnetization as well as neutron scattering experiments indicate the existence of three phase transitions. Neutron scattering, specific heat and magnetization suggest a canted ferromagnetic order beneath the first transition at 6.4 K. A second transition seen by specific heat is close by in zero field at 6.6 K, but strongly field dependent. By specific heat and susceptibility a third transition at 18.2 K is identified. The nature of the latter two transitions are unknown yet and require further investigations.