Browsing by Author "Granovsky, Sergey"

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    Open Access
    Data Underpinning: Magnetic phase diagram of rouaite, Cu₂⁢(OH)₃⁢NO₃
    (Technische Universität Dresden, 2024-11-04) Peets, Darren Campbell; Mannathanath Chakkingal, Aswathi; Kulbakov, Anton A.; Grumbach, Justus; Pavlovskii, Nikolai S.; Stockert, Ulrike; Parui, Kaushick Krishnakanta; Avdeev, Maxim; Kumar, Ramender; Niwata, Issei; Häußler, Ellen; Gumeniuk, Roman; Stewart, J. Ross; Tellam, James P.; Pomjakushin, Vladimir; Granovsky, Sergey; Doerr, Mathias; Hassinger, Elena; Zherlitsyn, Sergei; Ihara, Yoshihiko; Inosov, Dmytro S.
    This contains the data underpinning our recent paper on rouaite, Cu₂⁢(OH)₃⁢NO₃, published in Phys. Rev. B 110, 054442 (2024). The abstract of the article is reproduced below: Spinon-magnon mixing was recently reported in botallackite Cu2⁢(OH)3⁢Br with a uniaxially compressed triangular lattice of Cu2+ quantum spins [H. Zhang et al., Phys. Rev. Lett. 125, 037204 (2020)]. Its nitrate counterpart rouaite, Cu2⁢(OH)3⁢NO3, has a highly analogous structure and might be expected to exhibit similar physics. To lay a foundation for research on this material, we clarify rouaite's magnetic phase diagram and identify both low-field phases. The low-temperature magnetic state consists of alternating ferromagnetic and antiferromagnetic chains, as in botallackite, but with additional canting, leading to net moments on all chains which rotate from one chain to another to form a 90∘ cycloidal pattern. The higher-temperature phase is a helical modulation of this order, wherein the spins rotate from one Cu plane to the next. This extends to zero temperature for fields perpendicular to the chains, leading to a set of low-temperature field-induced phase transitions. Rouaite may offer another platform for spinon-magnon mixing, while our results suggest a delicate balance of interactions and high tunability of the magnetism.
  • Item
    Open Access
    Data Underpinning: Stacking Disorder in Novel ABAC-Stacked Brochantite
    (Technische Universität Dresden, 2025-01-16) Mannathanath Chakkingal, Aswathi; Fuller, Chloe; Avdeev, Maxim; Gumeniuk, Roman; Rahn, Marein C.; Pabst, Falk; Wang, Yiran; Granovsky, Sergey; 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.