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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">najo</journal-id><journal-title-group><journal-title xml:lang="en">Nanosystems: Physics, Chemistry, Mathematics</journal-title><trans-title-group xml:lang="ru"><trans-title>Наносистемы: физика, химия, математика</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">2220-8054</issn><issn pub-type="epub">2305-7971</issn><publisher><publisher-name>Университет ИТМО</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.17586/2220-8054-2020-11-1-30-35</article-id><article-id custom-type="elpub" pub-id-type="custom">najo-464</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>PHYSICS</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ФИЗИКА</subject></subj-group></article-categories><title-group><article-title>The Lagrange variety approach applied to frustrated classical wheels</article-title><trans-title-group xml:lang="ru"><trans-title></trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Florek</surname><given-names>W.</given-names></name></name-alternatives><bio xml:lang="en"><p>ul. Uniwersytetu Poznanskiego 2, 61-614 Poznan</p></bio><email xlink:type="simple">wojciech.florek@amu.edu.pl</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Marlewski</surname><given-names>A.</given-names></name></name-alternatives><bio xml:lang="en"><p>ul. Piotrowo 3A, 60-965 Poznan</p></bio><xref ref-type="aff" rid="aff-2"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Kamieniarz</surname><given-names>G.</given-names></name></name-alternatives><bio xml:lang="en"><p>ul. Uniwersytetu Poznanskiego 2, 61-614 Poznan</p></bio><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="western" xml:lang="en"><surname>Antkowiak</surname><given-names>M.</given-names></name></name-alternatives><bio xml:lang="en"><p>ul. Uniwersytetu Poznanskiego 2, 61-614 Poznan</p></bio><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff xml:lang="en" id="aff-1"><institution>Adam Mickiewicz University, Faculty of Physics</institution><country>Poland</country></aff><aff xml:lang="en" id="aff-2"><institution>Poznan University of Technology, Institute of Mathematics</institution><country>Poland</country></aff><pub-date pub-type="collection"><year>2020</year></pub-date><pub-date pub-type="epub"><day>31</day><month>07</month><year>2025</year></pub-date><volume>11</volume><issue>1</issue><elocation-id>30–35</elocation-id><permissions><copyright-statement>Copyright &amp;#x00A9; Florek W., Marlewski A., Kamieniarz G., Antkowiak M., 2025</copyright-statement><copyright-year>2025</copyright-year><copyright-holder xml:lang="ru">Florek W., Marlewski A., Kamieniarz G., Antkowiak M.</copyright-holder><copyright-holder xml:lang="en">Florek W., Marlewski A., Kamieniarz G., Antkowiak M.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://nanojournal.ifmo.ru/jour/article/view/464">https://nanojournal.ifmo.ru/jour/article/view/464</self-uri><abstract><p>The Lagrange variety approach introduced by Schmidt and Luban [J. Phys. A: Math. Gen. 36, 6351 (2003)] is applied to geometrically frustrated wheels (centered regular polygons). It is shown that the lowest energy configurations are planar or collinear. The latter one, characteristic for nonfrustrated classical systems, is also observed in the presence of competing interactions in a well-determined range (0,αc) of the energy function parameter α. The ‘critical’ value αc = 1/4 is universal, i.e., it does not depend on a system size. In this domain, the geometric frustration is present, but there is no non-trivial degeneracy.</p></abstract><kwd-group xml:lang="en"><kwd>frustration</kwd><kwd>classical spin models</kwd><kwd>magnetic molecules</kwd><kwd>Lagrange variety</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Furrer A., Waldmann O. Magnetic cluster excitations. Rev. Mod. Phys., 2013, 85 (1), P. 367–420.</mixed-citation><mixed-citation xml:lang="en">Furrer A., Waldmann O. Magnetic cluster excitations. Rev. Mod. Phys., 2013, 85 (1), P. 367–420.</mixed-citation></citation-alternatives></ref><ref id="cit2"><label>2</label><citation-alternatives><mixed-citation xml:lang="ru">Timco G.A., McInnes E.J.L., Winpenny R.E.P. Physical studies of heterometallic rings: An ideal system for studying magnetically-coupled systems. Chem. Soc. Rev., 2013, 42 (4), P. 1796–1806.</mixed-citation><mixed-citation xml:lang="en">Timco G.A., McInnes E.J.L., Winpenny R.E.P. Physical studies of heterometallic rings: An ideal system for studying magnetically-coupled systems. Chem. Soc. Rev., 2013, 42 (4), P. 1796–1806.</mixed-citation></citation-alternatives></ref><ref id="cit3"><label>3</label><citation-alternatives><mixed-citation xml:lang="ru">McInnes E.J.L., Timco G.A., Whitehead G.F.S., Winpenny R.E.P. Heterometallic rings: Their physics and use as supramolecular building blocks. Angew. Chem. Int. Ed., 2015, 54 (48), 14244.</mixed-citation><mixed-citation xml:lang="en">McInnes E.J.L., Timco G.A., Whitehead G.F.S., Winpenny R.E.P. Heterometallic rings: Their physics and use as supramolecular building blocks. Angew. Chem. Int. Ed., 2015, 54 (48), 14244.</mixed-citation></citation-alternatives></ref><ref id="cit4"><label>4</label><citation-alternatives><mixed-citation xml:lang="ru">Ghirri A., Chiesa A., et al. Coherent spin dynamics in molecular Cr8Zn wheels. The J. Phys. Chem. Lett., 2015, 6 (24), 5062.</mixed-citation><mixed-citation xml:lang="en">Ghirri A., Chiesa A., et al. Coherent spin dynamics in molecular Cr8Zn wheels. The J. Phys. Chem. Lett., 2015, 6 (24), 5062.</mixed-citation></citation-alternatives></ref><ref id="cit5"><label>5</label><citation-alternatives><mixed-citation xml:lang="ru">Baker M.L., Lancaster T., et al. Studies of a large odd-numbered odd-electron metal ring: Inelastic neutron scattering and muon spin relaxation spectroscopy of Cr8Mn. Chemistry – A European Journal, 2016, 22 (5), P. 1779–1788.</mixed-citation><mixed-citation xml:lang="en">Baker M.L., Lancaster T., et al. Studies of a large odd-numbered odd-electron metal ring: Inelastic neutron scattering and muon spin relaxation spectroscopy of Cr8Mn. Chemistry – A European Journal, 2016, 22 (5), P. 1779–1788.</mixed-citation></citation-alternatives></ref><ref id="cit6"><label>6</label><citation-alternatives><mixed-citation xml:lang="ru">Woolfson R.J., Timco G.A., et al. [CrF(O2CtBu)2]9: Synthesis and characterization of a regular homometallic ring with an odd number of metal centers and electrons. Angew. Chem. Int. Ed., 2016, 55 (31), 8856.</mixed-citation><mixed-citation xml:lang="en">Woolfson R.J., Timco G.A., et al. [CrF(O2CtBu)2]9: Synthesis and characterization of a regular homometallic ring with an odd number of metal centers and electrons. Angew. Chem. Int. Ed., 2016, 55 (31), 8856.</mixed-citation></citation-alternatives></ref><ref id="cit7"><label>7</label><citation-alternatives><mixed-citation xml:lang="ru">Furukawa Y., Kiuchi K., et al. Evidence of spin singlet ground state in the frustrated antiferromagnetic ring Cr8Ni. Phys. Rev. B, 2009, 79 (13), 134416.</mixed-citation><mixed-citation xml:lang="en">Furukawa Y., Kiuchi K., et al. Evidence of spin singlet ground state in the frustrated antiferromagnetic ring Cr8Ni. Phys. Rev. B, 2009, 79 (13), 134416.</mixed-citation></citation-alternatives></ref><ref id="cit8"><label>8</label><citation-alternatives><mixed-citation xml:lang="ru">Baker M.L., Timco G.A., et al. A classification of spin frustration in molecular magnets from a physical study of large odd-numbered-metal, odd electron rings. Proc. Nat. Acad. Sci. USA, 2012, 109, P. 19113–19118.</mixed-citation><mixed-citation xml:lang="en">Baker M.L., Timco G.A., et al. A classification of spin frustration in molecular magnets from a physical study of large odd-numbered-metal, odd electron rings. Proc. Nat. Acad. Sci. USA, 2012, 109, P. 19113–19118.</mixed-citation></citation-alternatives></ref><ref id="cit9"><label>9</label><citation-alternatives><mixed-citation xml:lang="ru">Antkowiak M., Kozłowski P., et al. Detection of ground states in frustrated molecular rings by in-field local magnetization profiles. Phys. Rev. B, 2013, 87 (18), 184430.</mixed-citation><mixed-citation xml:lang="en">Antkowiak M., Kozłowski P., et al. Detection of ground states in frustrated molecular rings by in-field local magnetization profiles. Phys. Rev. B, 2013, 87 (18), 184430.</mixed-citation></citation-alternatives></ref><ref id="cit10"><label>10</label><citation-alternatives><mixed-citation xml:lang="ru">Kozłowski P. Frustration and quantum entanglement in odd-membered ring-shaped chromium nanomagnets. Phys. Rev. B, 2015, 91 (17), 174432.</mixed-citation><mixed-citation xml:lang="en">Kozłowski P. Frustration and quantum entanglement in odd-membered ring-shaped chromium nanomagnets. Phys. Rev. B, 2015, 91 (17), 174432.</mixed-citation></citation-alternatives></ref><ref id="cit11"><label>11</label><citation-alternatives><mixed-citation xml:lang="ru">Owerre S.A., Nsofini J. Antiferromagnetic molecular nanomagnets with odd-numbered coupled spins. Europhy. Lett. (EPL), 2015, 110 (4), 47002.</mixed-citation><mixed-citation xml:lang="en">Owerre S.A., Nsofini J. Antiferromagnetic molecular nanomagnets with odd-numbered coupled spins. Europhy. Lett. (EPL), 2015, 110 (4), 47002.</mixed-citation></citation-alternatives></ref><ref id="cit12"><label>12</label><citation-alternatives><mixed-citation xml:lang="ru">Garlatti E., Bordignon S., et al. Relaxation dynamics in the frustrated Cr9 antiferromagnetic ring probed by NMR. Phys. Rev. B, 2016, 93 (2), 024424.</mixed-citation><mixed-citation xml:lang="en">Garlatti E., Bordignon S., et al. Relaxation dynamics in the frustrated Cr9 antiferromagnetic ring probed by NMR. Phys. Rev. B, 2016, 93 (2), 024424.</mixed-citation></citation-alternatives></ref><ref id="cit13"><label>13</label><citation-alternatives><mixed-citation xml:lang="ru">Kamieniarz G., Florek W., Antkowiak M. Universal sequence of ground states validating the classification of frustration in antiferromagnetic rings with a single bond defect. Phys. Rev. B, 2015, 92 (14), 140411(R).</mixed-citation><mixed-citation xml:lang="en">Kamieniarz G., Florek W., Antkowiak M. Universal sequence of ground states validating the classification of frustration in antiferromagnetic rings with a single bond defect. Phys. Rev. B, 2015, 92 (14), 140411(R).</mixed-citation></citation-alternatives></ref><ref id="cit14"><label>14</label><citation-alternatives><mixed-citation xml:lang="ru">Florek W., Antkowiak M., Kamieniarz G. Sequences of ground states and classification of frustration in odd-numbered antiferromagnetic rings. Phys. Rev. B, 2016, 94 (22), 224421.</mixed-citation><mixed-citation xml:lang="en">Florek W., Antkowiak M., Kamieniarz G. Sequences of ground states and classification of frustration in odd-numbered antiferromagnetic rings. Phys. Rev. B, 2016, 94 (22), 224421.</mixed-citation></citation-alternatives></ref><ref id="cit15"><label>15</label><citation-alternatives><mixed-citation xml:lang="ru">Ako A.M., Waldmann O., et al. Odd-numbered Fe(III) complexes: Synthesis, molecular structure, reactivity, and magnetic properties. Inorg. Chem., 2007, 46 (3), P. 756–766.</mixed-citation><mixed-citation xml:lang="en">Ako A.M., Waldmann O., et al. Odd-numbered Fe(III) complexes: Synthesis, molecular structure, reactivity, and magnetic properties. Inorg. Chem., 2007, 46 (3), P. 756–766.</mixed-citation></citation-alternatives></ref><ref id="cit16"><label>16</label><citation-alternatives><mixed-citation xml:lang="ru">Garlatti E., Carretta S., et al. Theoretical design of molecular nanomagnets for magnetic refrigeration. Appl. Phys. Lett., 2013, 103, 202410.</mixed-citation><mixed-citation xml:lang="en">Garlatti E., Carretta S., et al. Theoretical design of molecular nanomagnets for magnetic refrigeration. Appl. Phys. Lett., 2013, 103, 202410.</mixed-citation></citation-alternatives></ref><ref id="cit17"><label>17</label><citation-alternatives><mixed-citation xml:lang="ru">Sharples J.W., Collison D., et al. Quantum signatures of a molecular nanomagnet in direct magnetocaloric measurements. Nature Commun., 2014, 5, 5321.</mixed-citation><mixed-citation xml:lang="en">Sharples J.W., Collison D., et al. Quantum signatures of a molecular nanomagnet in direct magnetocaloric measurements. Nature Commun., 2014, 5, 5321.</mixed-citation></citation-alternatives></ref><ref id="cit18"><label>18</label><citation-alternatives><mixed-citation xml:lang="ru">Kakaroni F.E., Collet A., et al. Constructing CrIII-centered heterometallic complexes: [NiII6CrIII] and [CoII6CrIII] wheels. Dalton Trans., 2018, 47 (1), P. 58–61.</mixed-citation><mixed-citation xml:lang="en">Kakaroni F.E., Collet A., et al. Constructing CrIII-centered heterometallic complexes: [NiII6CrIII] and [CoII6CrIII] wheels. Dalton Trans., 2018, 47 (1), P. 58–61.</mixed-citation></citation-alternatives></ref><ref id="cit19"><label>19</label><citation-alternatives><mixed-citation xml:lang="ru">Florek W., Kamieniarz G., Marlewski A. Universal lowest energy configurations in a classical Heisenberg model describing frustrated systems with wheel geometry. Phys. Rev. B, 2019, 100 (5), 054434.</mixed-citation><mixed-citation xml:lang="en">Florek W., Kamieniarz G., Marlewski A. Universal lowest energy configurations in a classical Heisenberg model describing frustrated systems with wheel geometry. Phys. Rev. B, 2019, 100 (5), 054434.</mixed-citation></citation-alternatives></ref><ref id="cit20"><label>20</label><citation-alternatives><mixed-citation xml:lang="ru">Wilson R.J. Introduction to Graph Theory. Addison Wesley Longman Ltd., London, 1996.</mixed-citation><mixed-citation xml:lang="en">Wilson R.J. Introduction to Graph Theory. Addison Wesley Longman Ltd., London, 1996.</mixed-citation></citation-alternatives></ref><ref id="cit21"><label>21</label><citation-alternatives><mixed-citation xml:lang="ru">Grajek M., Kopyciuk T., Florek W., Marlewski A. Collinear and non-collinear configurations in classical geometrically frustrated ring-shaped systems. Acta Phys. Pol. A, 2018, 133 (3), P. 417–419.</mixed-citation><mixed-citation xml:lang="en">Grajek M., Kopyciuk T., Florek W., Marlewski A. Collinear and non-collinear configurations in classical geometrically frustrated ring-shaped systems. Acta Phys. Pol. A, 2018, 133 (3), P. 417–419.</mixed-citation></citation-alternatives></ref><ref id="cit22"><label>22</label><citation-alternatives><mixed-citation xml:lang="ru">Popov A.P., Anisimov A.V., Eriksson O., Skorodumova N.V. Metastable noncollinear canted states from a phenomenological model of a symmetric ferromagnetic film. Phys. Rev. B, 2010, 81 (5), 054440.</mixed-citation><mixed-citation xml:lang="en">Popov A.P., Anisimov A.V., Eriksson O., Skorodumova N.V. Metastable noncollinear canted states from a phenomenological model of a symmetric ferromagnetic film. Phys. Rev. B, 2010, 81 (5), 054440.</mixed-citation></citation-alternatives></ref><ref id="cit23"><label>23</label><citation-alternatives><mixed-citation xml:lang="ru">Popov A.P., Rettori A., Pini M.G. Discovery of metastable states in a finite-size classical one-dimensional planar spin chain with competing nearest- and next-nearest-neighbor exchange couplings. Phys. Rev. B, 2014, 90 (13), 134418.</mixed-citation><mixed-citation xml:lang="en">Popov A.P., Rettori A., Pini M.G. Discovery of metastable states in a finite-size classical one-dimensional planar spin chain with competing nearest- and next-nearest-neighbor exchange couplings. Phys. Rev. B, 2014, 90 (13), 134418.</mixed-citation></citation-alternatives></ref><ref id="cit24"><label>24</label><citation-alternatives><mixed-citation xml:lang="ru">Popov A.P., Rettori A., Pini M.G. Spectrum of noncollinear metastable configurations of a finite-size discrete planar spin chain with a collinear ferromagnetic ground state. Phys. Rev. B, 2015, 92 (2), 024414.</mixed-citation><mixed-citation xml:lang="en">Popov A.P., Rettori A., Pini M.G. Spectrum of noncollinear metastable configurations of a finite-size discrete planar spin chain with a collinear ferromagnetic ground state. Phys. Rev. B, 2015, 92 (2), 024414.</mixed-citation></citation-alternatives></ref><ref id="cit25"><label>25</label><citation-alternatives><mixed-citation xml:lang="ru">Schmidt H.-J., Luban M. Classical ground states of symmetric Heisenberg spin systems. Journal of Physics A: Math. Gen., 2003, 36 (23), P. 6351–6378.</mixed-citation><mixed-citation xml:lang="en">Schmidt H.-J., Luban M. Classical ground states of symmetric Heisenberg spin systems. Journal of Physics A: Math. Gen., 2003, 36 (23), P. 6351–6378.</mixed-citation></citation-alternatives></ref><ref id="cit26"><label>26</label><citation-alternatives><mixed-citation xml:lang="ru">Schmidt H.-J. Theory of ground states for classical Heisenberg spin systems. Parts I–IV. 2017, arXiv: https://arxiv.org/abs/1701.02489,1707.02859,1707.06512,1710.00318.</mixed-citation><mixed-citation xml:lang="en">Schmidt H.-J. Theory of ground states for classical Heisenberg spin systems. Parts I–IV. 2017, arXiv: https://arxiv.org/abs/1701.02489,1707.02859,1707.06512,1710.00318.</mixed-citation></citation-alternatives></ref><ref id="cit27"><label>27</label><citation-alternatives><mixed-citation xml:lang="ru">Florek W., Marlewski A. Spectrum of some arrow-bordered circulant matrix. 2019, arXiv: https//arXiv.org/abs/1905.04807.</mixed-citation><mixed-citation xml:lang="en">Florek W., Marlewski A. Spectrum of some arrow-bordered circulant matrix. 2019, arXiv: https//arXiv.org/abs/1905.04807.</mixed-citation></citation-alternatives></ref><ref id="cit28"><label>28</label><citation-alternatives><mixed-citation xml:lang="ru">Toulouse G. Theory of the frustration effect in spin glasses: I. In Mezard M., Parisi G., Virasoro M.A.´ Spin Glass Theory and Beyond. World Scientific, Singapore: 1987, P. 99–103. Reprinted form: Toulouse G. Communcations de Physique. 1977, 2, P. 115–119.</mixed-citation><mixed-citation xml:lang="en">Toulouse G. Theory of the frustration effect in spin glasses: I. In Mezard M., Parisi G., Virasoro M.A.´ Spin Glass Theory and Beyond. World Scientific, Singapore: 1987, P. 99–103. Reprinted form: Toulouse G. Communcations de Physique. 1977, 2, P. 115–119.</mixed-citation></citation-alternatives></ref><ref id="cit29"><label>29</label><citation-alternatives><mixed-citation xml:lang="ru">Vannimenus J., Toulouse G. Theory of the frustration effect: II. Ising spins on a square lattice. J. Phys. C: Solid State Phys., 1977, 10 (18), P. L537–L542.</mixed-citation><mixed-citation xml:lang="en">Vannimenus J., Toulouse G. Theory of the frustration effect: II. Ising spins on a square lattice. J. Phys. C: Solid State Phys., 1977, 10 (18), P. L537–L542.</mixed-citation></citation-alternatives></ref><ref id="cit30"><label>30</label><citation-alternatives><mixed-citation xml:lang="ru">Pauling L. The structure and entropy of ice and of other crystals with some randomness of atomic arrangement. J. Am. Chem. Soc., 1935, 57 (12), P. 2680–2684.</mixed-citation><mixed-citation xml:lang="en">Pauling L. The structure and entropy of ice and of other crystals with some randomness of atomic arrangement. J. Am. Chem. Soc., 1935, 57 (12), P. 2680–2684.</mixed-citation></citation-alternatives></ref><ref id="cit31"><label>31</label><citation-alternatives><mixed-citation xml:lang="ru">Wannier G.H. Antiferromagnetism. The triangular Ising net. Phys. Rev., 1950, 79 (2), P. 357–364.</mixed-citation><mixed-citation xml:lang="en">Wannier G.H. Antiferromagnetism. The triangular Ising net. Phys. Rev., 1950, 79 (2), P. 357–364.</mixed-citation></citation-alternatives></ref><ref id="cit32"><label>32</label><citation-alternatives><mixed-citation xml:lang="ru">Giampaolo S.M., Gualdi G., Monras A., Illuminati F. Characterizing and quantifying frustration in quantum many-body systems. Phys. Rev. Lett., 2011, 107 (26), 260602.</mixed-citation><mixed-citation xml:lang="en">Giampaolo S.M., Gualdi G., Monras A., Illuminati F. Characterizing and quantifying frustration in quantum many-body systems. Phys. Rev. Lett., 2011, 107 (26), 260602.</mixed-citation></citation-alternatives></ref><ref id="cit33"><label>33</label><citation-alternatives><mixed-citation xml:lang="ru">Binder K., Young A.P. Spin glasses: Experimental facts, theoretical concepts, and open questions. Rev. Mod. Phys., 1986, 58, P. 801–967.</mixed-citation><mixed-citation xml:lang="en">Binder K., Young A.P. Spin glasses: Experimental facts, theoretical concepts, and open questions. Rev. Mod. Phys., 1986, 58, P. 801–967.</mixed-citation></citation-alternatives></ref><ref id="cit34"><label>34</label><citation-alternatives><mixed-citation xml:lang="ru">Lacorre P. The constraint functions: an attempt to evaluate the constraint rate inside structures that undergo ordered magnetic frustration. J. Phys. C: Solid State Phys., 1987, 20 (29), P. L775–L781.</mixed-citation><mixed-citation xml:lang="en">Lacorre P. The constraint functions: an attempt to evaluate the constraint rate inside structures that undergo ordered magnetic frustration. J. Phys. C: Solid State Phys., 1987, 20 (29), P. L775–L781.</mixed-citation></citation-alternatives></ref><ref id="cit35"><label>35</label><citation-alternatives><mixed-citation xml:lang="ru">Florek W., Antkowiak M., Kamieniarz G. The Kahn degenerate frustration points and the Lieb-Mattis level order in heterometallic wheel molecules with competing interactions. J. Mag. Mag. Mater., 2019, 487, 165326.</mixed-citation><mixed-citation xml:lang="en">Florek W., Antkowiak M., Kamieniarz G. The Kahn degenerate frustration points and the Lieb-Mattis level order in heterometallic wheel molecules with competing interactions. J. Mag. Mag. Mater., 2019, 487, 165326.</mixed-citation></citation-alternatives></ref></ref-list><fn-group><fn fn-type="conflict"><p>The authors declare that there are no conflicts of interest present.</p></fn></fn-group></back></article>
