Naslov
Incommensurate magnetic ordering in Cu2Te2O5X2 (X=Cl, Br) studied by single crystal neutron diffraction

Autori
Zaharko, O ; Ronnow, H ; Mesot, J ; Crowe, SJ ; Paul, DMcK ; Brown, PJ ; Daoud-Aladine, A ; Meents, A ; Wagner, A ; Prester, Mladen ; Berger, Helmuth

Izvornik
Physical Review B (1098-0121) 73 (2006); 1-7

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
magnetic order; antiferromagnetism; quantum magnets

Sažetak
Polarized and unpolarized neutron-diffraction studies have been carried out on single crystals of the coupled spin tetrahedra systems Cu2Te2O5X2 (X=Cl, Br). A model of the magnetic structure associated with the propagation vectors k'_Cl=(-0.150, 0.422, 1/2) and k'_Br=(-0.172, 0.356, 1/2) and stable below TN=18K for C=Cl and TN=11K for X=Br is proposed. A feature of the model, common to both the bromide and the chloride, is a canted coplanar motif for the four Cu2+ spins on each tatrahedron which rotates on a helix from cell to cell following the propagation vector. The Cu2+ magnetic moment determined for X=Br, 0.395(5) mu_B, is significantly less than for X=Cl, 0.88(1) mu_B at 2 K. The magnetic structure of the chloride associated with the wave vector k' differs from that determined previously for the wave vector k=(0.150, 0.422, 1/2) (O.Zaharko et al., Phys.Rev.Lett 93, 217206(E) (2004)).

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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