Magnetic structure of BaCaFe4O8-analysis of neutron diffraction measurements

Crystal structure and magnetic properties of some new hexagonal ferrites (Ba2Sn2MeFe10−xGaxO22) with the QS-structure

“…The net-moment obtained by using the found occupation rates and the theoretical spin-only values show the best agreement with the experimentally obtained moments. The moments calculated with the refined moments from the neutron diffraction experiments are always considerable lower than the moments obtained from the magnetization measurements at 4.2 K. This is not unusual, and is also found in several other investigations [15,19,20].…”

“…The model used for the refinements has the magnetic moments of the atoms at the tetrahedral sites in a direction opposite to the moments of the octahedral sites. At the two BaO3-1ayers, the moments of the bounding tetrahedral sites (Tetr(2)) are coupled antiferromagnetically, in a way already suggested [2] and reported for the magnetic structure of BaCaFe40 s [15]. In the spinel-block and the bounding O4-1ayer of the Q-block there are 4 tetrahedral sites occupied and 9 octahedral sites, two of the octahedral sites are occupied by Sn, but nevertheless there are always more magnetic moments at the octahedral sites, resulting in a net magnetic moment for the block between the BaO3-1ayers.…”

Antiferromagnetic structure of barium strontium tetraferrate(III), BaSrFe4O8

“…The magnetic structures of the two compounds are very similar (Abbas, Mostafa & Fayek, 1982). From a structural point of view the substitution of strontium by calcium with smaller ionic radius may be expected to result in a decrease in the c value leaving the a value unchanged.…”

“…The distance between the Fe 3÷ ions decreases, and this means that the magnetic interactions are stronger in the case of the Ca compound. Detailed data on the magnetic structure of BaCaFe408 are given elsewhere (Abbas et al, 1982).…”

Al doping effect on magnetic phase transitions of magnetoelectric hexaferrite Ba0.7Sr1.3Zn2Chang1, Lee2, Song3 et al. 2012Phys. Rev. B461260View full textAdd to dashboardCite

“…The former examples include BaCaFe 4 O 8 or BaSrFe 4 O 8 , in which Fe ions are found at tetrahedral sites only. 39,40 In contrast, Fe ions in BiFeO 3 occupy octahedral sites only, and its modulated magnetic structure shows no particular indication of magnetic anisotropy. 41 All other hexaferrites possess both types, between which octahedral sites are found more frequently than tetrahedral sites.…”