Proof of the elusive high-temperature incommensurate phase in CuO by spherical neutron polarimetry
Qureshi, Navid (Institut Laue Langevin)
Ressouche, Eric (Université Grenoble Alpes)
Mukhin, Alexander (Prokhorov General Physics Institute)
Gospodinov, Marin (Bulgarian Academy of Sciences. Institute of Solid State Physics)
Skumryev, Vassil (Universitat Autònoma de Barcelona. Departament de Física)

Data:	2020
Resum:	After three decades of research on CuO, the AF3 phase is proven by neutrons, which clears up the mystery of symmetry-broken phases. CuO is the only known binary multiferroic compound, and due to its high transition temperature into the multiferroic state, it has been extensively studied. In comparison to other prototype multiferroics, the nature and even the existence of the high-temperature incommensurate paraelectric phase (AF3) were strongly debated-both experimentally and theoretically-since it is stable for only a few tenths of a kelvin just below the Néel temperature. Until now, there is no proof by neutron diffraction techniques owing to its very small ordered Cu magnetic moment. Here, we demonstrate the potential of spherical neutron polarimetry, first, in detecting magnetic structure changes, which are not or weakly manifest in the peak intensity and, second, in deducing the spin arrangement of the so far hypothetic AF3 phase. Our findings suggest two coexisting spin density waves emerging from an accidental degeneracy of the respective states implying a delicate energy balance in the spin Hamiltonian.
Ajuts:	European Commission 731096 Agencia Estatal de Investigación MAT2017-85232-R Ministerio de Economía y Competitividad SEV-2015-0496 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1377
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Publicat a:	Science advances, Vol. 6, issue 7 (Feb. 2020) , eaay7661, ISSN 2375-2548

DOI: 10.1126/sciadv.aay7661
PMID: 32110734

8 p, 554.4 KB

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