SKM 2023 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 44: Frustrated Magnets II
MA 44.9: Vortrag
Donnerstag, 30. März 2023, 17:15–17:30, HSZ 403
Spin-liquid and Spin-glass states in Frustrated Tetragonal Pyrochlore Zn0.8Cu0.2FeMnO4 — •Suchit Kumar Jena1, Manfred Reehuis2, and Subhash Thota1 — 1Department of Physics, Indian Institute of Technology Guwahati, Assam-781039, India — 2Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany
Spinel (AB2O4) Pyrochlore lattices are capable of generating high degree of magnetic frustration owing to tunable competing exchange interactions achieved via suitable magnetic elements on B site together with non-magnetic A site, which leads to quantum spin-liquid/Ice state [1]. One such compound is cubic ZnFe2O4, which manifests high magnetic frustration index (f≃12) with antiferromagnetic Néel temperature, TN∼10K [2]. Our results based on the neutron powder diffraction analysis shows that polycrystalline tetragonal Zn0.8Cu0.2FeMnO4 (ZCFMO) lacks presence of long-range magnetic ordering. The dynamic ac magnetic susceptibility (χ′ and χ″) measurements show multiple anomalies across 9K, 47K and 79K. Frequency dispersion in the loss spectrum (χ″(f,T)) analyzed by employing empirical scaling-laws such as Vogel-Fulcher law and Power Law: τ=τ0[(T−TSG)/TSG]−zν, yields cluster spin-glass state in ZCFMO with the spin freezing temperature (TSG) at 41.8K and critical exponent zν=8.9, below the ferrimagnetic Néel temperature TFiM≃79K. These results are further supported by the heat capacity (Cp(T)) studies. Below 9K, Cp ∼ T2, indicates co-existence of spin-glass and spin-liquid states in ZCFMO. [1] Phys. Rev. B 28, 1 (1983). [2] Phys. Rev. B 66, 064401 (2002).