Complex magnetic incommensurability and electronic charge transfer through the ferroelectric transition in multiferroic Co3TeO6

Abstract

Polarized and unpolarized neutron diffractions have been carried out to investigate the nature of the magnetic structures and transitions in monoclinic Co3TeO6. As the temperature is lowered below 26 K long range order develops, which is fully incommensurate (ICM) in all three crystallographic directions. Below 19.5 K additional commensurate magnetic peaks develop, consistent with the Γ4 irreducible representation, along with a splitting of the ICM peaks along the h direction which indicates that there are two separate sets of magnetic modulation vectors. Below 18 K, this small additional magnetic incommensurability disappears, ferroelectricity develops, an additional commensurate magnetic structure consistent with Γ3 irreducible representation appears, and the k component of the ICM wave vector disappears. Synchrotron x-ray diffraction measurements demonstrate that there is a significant shift of the electronic charge distribution from the Te ions at the crystallographic 8 f sites to the neighboring Co and O ions. These results, together with the unusually small electric polarization, its strong magnetic field dependence, and the negative thermal expansion in all three lattice parameters, suggest this material is an antiferroelectric. Below15 K the k component of the ICM structure reappears, along with second-order ICM Bragg peaks, which polarized neutron data demonstrate are magnetic in origin.

Incommensurate and multiple- q magnetic misfit order in the frustrated quantum spin ladder material antlerite Cu3SO4(OH)4Kulbakov1, Sadrollahi2, Rasch3 et al. 2022Phys. Rev. B2000View full textAdd to dashboardCite

“…An even rarer aspect of the multiple-q phase in antlerite is that it combines commensurate antiferromagnetic order on one magnetic site with incommensurate order on another. The only other reported example of such a situation is Co 3 TeO 6 [46][47][48], whose magnetic sublattice includes five magnetic Co sites (including both octahedral and tetrahedral coordination) and has an additional antiferroelectric transition within one of its magnetically ordered phases. This structural complexity has greatly complicated the identification and investigation of its magnetic order, and led to the papers cited here to very different determinations of several of its phases.…”

The Cobalt(II) Oxidotellurate(IV) Hydroxides Co2(TeO3)(OH)2 and Co15(TeO3)14(OH)2

“…Next to the structural variety of corresponding cobalt(II) oxidotellurates resulting from the two possible oxidation states of Te and the condensation grade of the oxidotellurate anions, some of the phases in this system are of interest due to their interesting magnetic and electronic behaviors. This includes CoTe IV O 3 [1,2], CoTe VI O 4 [3], Co 3 Te VI O 6 [4][5][6][7][8] and Co 5 Te VI O 8 [9]. Most of these phases have been prepared by conventional solid-state reactions at varying pressure conditions [1-4,7-9], or by the application of chemical vapor transport reactions [5,6,10].…”

“…This includes CoTe IV O 3 [1,2], CoTe VI O 4 [3], Co 3 Te VI O 6 [4][5][6][7][8] and Co 5 Te VI O 8 [9]. Most of these phases have been prepared by conventional solid-state reactions at varying pressure conditions [1-4,7-9], or by the application of chemical vapor transport reactions [5,6,10]. Other phases in the Co/Te/O system, for which crystal structure determinations have been carried out so far, include Co 6 Te IV 5 O 16 [11], CoTe IV 6 O 13 [12] and Co 2 Te IV 3 O 8 [13].…”

Single-Crystal Structure of HP-Sc2TeO6 Prepared by High-Pressure/High-Temperature Synthesis

“…M 3 TeO 6 (M = Ni, Co, Mn, Cu) compounds exhibit antiferromagnetic ordering at low temperatures combined with magnetoelectric properties. These materials are classified as type-II multiferroics and have recently gained great importance [1][2][3][4][5][6][7][8]. The structural diversity of oxotellurate compounds is related on Te 4+ and Te 6+ as well as mixed valent Te 4+ /Te 6+ combinations.…”