NEUTRON-DIFFRACTION STUDY ON NA-JAROSITES AND K-JAROSITES

Powder neutron-diffraction measurements of the frustrated kagome latti ce antiferromagnets Na- and K-jarosites (AFe(3)(OH)(6)(SO4)(2): A = Na and K) were carried out. The determined magnetic structure at 10 K is the so-called q = 0 structure and found to be different from one repo rted previously for K-jarosite. The intensities of magnetic reflection s show slow decreasing with increasing temperature near T-N and seem t o imply successive phase transitions observed ina recent NMR study. (C ) 1998 Elsevier Science B.V. All rights reserved.