Browsing by Author "Korshunov, Artem"

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Open Access
Data Underpinning: Disorder-driven magnetic duality in the spin-½ system ktenasite, Cu₂.₇Zn₂.₃(SO₄)₂(OH)₆·6H₂O
(Technische Universität Dresden, 2025-10-17) Parui, Kaushick K.; Kulbakov, Anton A.; Gumeniuk, Roman; Carrillo-Aravena, Eduardo; Fernández-Díaz, María Teresa; Savvin, Stanislav; Korshunov, Artem; Granovsky, Sergey; Doert, Thomas; Inosov, Dmytro S.; Peets, Darren C.
Article abstract: Disorder in frustrated quantum systems can critically influence their magnetic ground states and drive exotic magnetic behavior. In the S = ½ system ktenasite, Cu₂.₇Zn₂.₃(SO₄)₂(OH)₆·6H₂O, we show that structural disorder drives an unexpected dimensional crossover and stabilizes a rare coexistence of distinct magnetic states. Neutron diffraction reveals significant Cu/Zn mixing at the Cu2 site, which tunes the Cu²⁺ sublattice from a two-dimensional scalene-distorted triangular lattice into a one-dimensional spin-chain network. Magnetic susceptibility, neutron diffraction, ac susceptibility, and specific heat measurements collectively indicate magnetic duality: a coexistence of incommensurate long-range magnetic order below TN = 4 K and a cluster spin-glass state with Tf = 3.28 K at f = 10 Hz. Our findings highlight ktenasite as a rare platform where structural disorder tunes the effective dimensionality and stabilizes coexisting ordered and glassy magnetic phases, offering a unique opportunity to explore the interplay of frustration, disorder, and dimensional crossover in quantum magnets.
Open Access
Data Underpinning: Stacking Disorder in Novel ABAC-Stacked Brochantite, Cu₄SO₄(OH)₆
(Technische Universität Dresden, 2025-01-16) Mannathanath Chakkingal, Aswathi; Fuller, Chloe; Avdeev, Maxim; Gumeniuk, Roman; Parui, Kaushick K.; Rahn, Marein C.; Pabst, Falk; Wang, Yiran; Granovsky, Sergey; Korshunov, Artem; Chernyshov, Dmitry; Inosov, Dmytro S.; Peets, Darren C.
Abstract of the accompanying article: In geometrically frustrated magnetic systems, weak interactions or slight changes to the structure can tip the delicate balance of exchange interactions, sending the system into a different ground state. Brochantite, Cu₄SO₄(OH)₆, has a copper sublattice composed of distorted triangles, making it a likely host for frustrated magnetism, but exhibits stacking disorder. The lack of synthetic single crystals has limited research on the magnetism in brochantite to powders and natural mineral crystals. We grew crystals which we find to be a new polytype with a tendency toward ABAC stacking and some anion disorder, alongside the expected stacking disorder. Comparison to previous results on natural mineral specimens suggests that cation disorder is more deleterious to the magnetism than anion and stacking disorder. Our specific heat data suggest a double transition on cooling into the magnetically ordered state.