Heat Capacities of Natural Antlerite and Brochantite at Low Temperature

Bissengaliyeva, Мira R.; Bekturganov, N. S.; Gogol, Daniil B.; Taimassova, Shynar T.; Кoketai, Temirgaly; Bespyatov, M.A.

doi:10.1021/je400130b

Cited by 6 publications

(5 citation statements)

References 11 publications

(31 reference statements)

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“…Layers of alternating edge-and corner-sharing chains (figure 1, right) are well separated by SO 4 sulphate groups and water molecules. A somewhat similar structure without water molecules has been reported for the mineral brochantite Cu 4 (OH) 6 SO 4 [39,40] that, however, features a much smaller interlayer separation, hence substantial interlayer couplings can be expected. In this paper, we focus on the magnetism of langite, where individual structural planes should be very weakly coupled magnetically and sufficiently pure natural samples of this mineral are available.…”

Section: Introductionsupporting

confidence: 68%

Interplay of magnetic sublattices in langite Cu₄(OH)₆SO₄· 2H₂O

et al. 2016

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Magnetic and crystallographic properties of the mineral langite Cu 4 (OH) 6 SO 2 4 · H 2 O are reported. Thermodynamic measurements combined with a microscopic analysis, based on density-functional bandstructure calculations, identify a quasi-two-dimensional (2D), partially frustrated spin-1/2 lattice resulting in the low Néel temperature of T 5.7 N  K. This spin lattice splits into two parts with predominant ferro-and antiferromagnetic (AFM) exchange couplings, respectively. The former, ferromagnetic (FM) part is prone to the long-range magnetic order and saturates around 12 T, where the magnetization reaches 0.5 B m /Cu. The latter, AFM part features a spin-ladder geometry and should evade long-range magnetic order. This representation is corroborated by the peculiar temperature dependence of the specific heat in the magnetically ordered state. We argue that this separation into ferro-and antiferromagnetic sublattices is generic for quantum magnets in Cu 2+ oxides that combine different flavors of structural chains built of CuO 4 units. To start from reliable structural data, the crystal structure of langite in the 100-280 K temperature range has been determined by single-crystal x-ray diffraction, and the hydrogen positions were refined computationally.chains develop incommensurate spin correlations and helical magnetic order [8,9], although few instances of FM intrachain spin order are known as well [10,11]. The helical spin arrangement observed in simple binary compounds CuCl 2 [12] and CuBr 2 [13] and in more complex materials like linarite PbCu(OH) 2 SO 4 [14], all being frustrated J J 1 2 spin chains, may trigger electric polarization induced by the magnetic order, thus leading to multiferroic behavior [15-18]. Additionally, small interactions beyond the isotropic Heisenberg model lead to an intricate magnetic phase diagram, including multipolar (three-magnon) phases, which has been studied recently [19]. However, the complex interplay of frustration and anisotropy needs further investigations on different systems as, e.g., LiCuVO 4 [20-23]. One may naturally ask what happens when two types of spin chains, those with edge-and corner-sharing geometries, are placed next to each other within one material. Spin systems comprising several magnetic OPEN ACCESS RECEIVED =. A more detailed description of the procedure can be found, e.g., in [31,54]. Alternatively, strong electron correlations are added on top of LDA by the LSDA+U method in a mean-field way and are thus included in the self-consistent procedure. This allows for calculating total exchange constants J J J ij ij ij FM AFM ( ) m = J J J 81

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Section: Introductionsupporting

confidence: 68%

Interplay of magnetic sublattices in langite Cu₄(OH)₆SO₄· 2H₂O

et al. 2016

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“…This system, with the chemical formula Cu 3 (MoO 4 )(OH) 4 , crystallizes in an orthorhombic structure described by the space group P nnm, in which CuO 4 plaquettes form triple chains that are parallel to the c axis [224,225]. In this respect, the structure resembles that of the sulfate mineral antlerite, Cu 3 (SO 4 )(OH) 4 , in which the edge-sharing Cu(1) central chain shows an idle-spin behaviour, and only the corner-sharing Cu(2) outer chains order magnetically below T N ≈ 5.3 K into a collinear structure characterized by an antiparallel orientation of spins in the opposite FM aligned chains [226][227][228]. An isostructural synthetic compound Cu 3 (SeO 4 )(OH) 4 , on the other hand, stabilizes a more complex cycloidal magnetic structure among the FM chains that locks into the commensurate 1 7 0 0 propagation vector at low temperatures [227].…”

Section: Szenicsite and Antlerite: Frustrated Spin Chains Near The Mamentioning

confidence: 99%

Quantum magnetism in minerals

Inosov

2018

Advances in Physics

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The discovery of magnetism by the ancient Greeks was enabled by the natural occurrence of lodestone -a magnetized version of the mineral magnetite. Nowadays, natural minerals continue to inspire the search for novel magnetic materials with quantum-critical behaviour or exotic ground states such as spin liquids. The recent surge of interest in magnetic frustration and quantum magnetism was largely encouraged by crystalline structures of natural minerals realizing pyrochlore, kagome, or triangular arrangements of magnetic ions. As a result, names like azurite, jarosite, volborthite, and others, which were barely known beyond the mineralogical community a few decades ago, found their way into cutting-edge research in solid-state physics. In some cases, the structures of natural minerals are too complex to be synthesized artificially in a chemistry lab, especially in single-crystalline form, and there is a growing number of examples demonstrating the potential of natural specimens for experimental investigations in the field of quantum magnetism. On many other occasions, minerals may guide chemists in the synthesis of novel compounds with unusual magnetic properties. The present review attempts to embrace this quickly emerging interdisciplinary field that bridges mineralogy with low-temperature condensed-matter physics and quantum chemistry. PACS: 75.30.-m -intrinsic properties of magnetically ordered materials; 75.10.Jm -models of magnetic ordering, including quantum spin frustration; 91.60.Pn -magnetic properties of minerals.

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“…The found values of the thermodynamic functions of natural chalcanthite (the heat capacity, entropy, the change of enthalpy, the reduced thermodynamic potential) are shown in Table 2. At temperatures below 10 K in the heat capacity of chalcanthite we observed a noticeable deviation from the normal course of the curve associated with the completion of the phase transition, the maximum of which lies below 4 K. To single out the anomalous component we used the method that we had used to single out the magnetic component in the heat capacity of other natural sulfates of copper -antlerite and brochantite [37].…”

Section: Resultsmentioning

confidence: 99%

“…The results of crystallographic studies show that the presence of the spatial system of copper chains is typical for the crystal structure of chalcanthite. The copper chains are available in other minerals of copper, too [30,31], for which the ordering of magnetic moments at low temperatures [32][33][34][35][36][37] is characteristic.…”

Section: Introductionmentioning

confidence: 99%