Chemical tuning of the interlayer magnetic coupling in Tl Co2Se2-xSx
2006 (English)In: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 299, no 1, 53-63 p.Article in journal (Refereed) Published
The system TlCo2Se2-xSx has been thoroughly investigated by neutron powder diffraction and SQUID magnetometry. TlCo2Se2-xSx is a layered tetragonal structure containing atomic cobalt layers separated by a distance of 6.4 Å in the sulphide and 6.8 Å in the selenide. The solid solubility of isovalent selenium and sulphur atoms in the structure makes it possible to continuously vary the interlayer distance and thereby tune the magnetic coupling between the Co-layers. At low temperatures, the Co-atoms are ferromagnetically ordered within the layers and magnetic moments lie in the ab-plane. However, these Co-moments form a helical magnetic structure that prevails for 0x1.5 with a gradual decrease of the angle between adjacent Co-layers from 122° to 39°. For x1.75, a collinear ferromagnetic structure is stable. The relationship between the coupling angle and the Co-interlayer separation shows an almost linear behaviour. The helical phase contains no net spontaneous magnetic moment up to TlCo2SeS, where a small net magnetic moment appears that increases until the ferromagnetic structure is found for 1.75x2.0.
Place, publisher, year, edition, pages
2006. Vol. 299, no 1, 53-63 p.
Layered magnetic structure, Ferromagnetism, Antiferromagnetism, ThCr2Si2 type, Incommensurate helix, TlCo2Se2, TlCo2S2
Engineering and Technology
IdentifiersURN: urn:nbn:se:uu:diva-93542DOI: 10.1016/j.jmmm.2005.03.082OAI: oai:DiVA.org:uu-93542DiVA: diva2:167050