Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 35: PhD Symposium: Quantum Phase Transitions: Emergent Phenomena beyond Elementary Excitations (organized by MA, jDPG)

TT 35.16: Poster

Dienstag, 17. März 2015, 16:15–16:30, EB 301

Tuning ZrFe₄Si₂ by Ge substitution: confirming the proximity to a magnetic quantum critical point — •Katharina Weber^1,2, Nandang Mufti¹, Til Goltz², Theo Woike³, Hans-Henning Klauß², Christoph Bergmann¹, Helge Rosner¹, and Christoph Geibel¹ — ¹Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — ²Institute of Solid State Physics, TU Dresden, Germany — ³Institute for Structural Physics, TU Dresden, Germany

Magnetic systems with reduced dimensionality or frustration are attracting strong interest because these features lead to an increase of quantum fluctuations which often results in unusual, very interesting properties. Our previous studies evidence the AFe₄X₂ family (A = Y, Lu, Zr and X = Ge, Si) to cover the whole regime from frustrated antiferromagnetic (AFM) order up to the quantum critical point (QCP) separating the frustrated AFM ground state from the paramagnetic ground state. ZrFe₄Si₂ showed evidence for an unusual type of weak magnetic order and was therefore suspected to be near the QCP. In order to get a deeper insight into its ground state, we performed a detailed study of Ge substituted ZrFe₄Si₂, where Ge is suspected to stabilize the magnetic state because of a negative chemical pressure effect. We synthesized polycrystalline samples of ZrFe₄(Si_1−xGe_x)₂ with x=2 % to 50 % and investigated their magnetic, thermodynamic, structural and transport properties. As expected with increasing Ge content the magnetic state is stabilized towards a well defined AFM order at high Ge content. This confirms the near-by QCP in ZrFe₄Si₂.