LIFEP2O7 - STRUCTURE AND MAGNETIC-PROPERTIES

In order to compare the structural and magnetic properties of the diphosphates AFeP2O7 (A=Li, Na, K), the structure of the LiFeP2O7 compound was redetermined and the magnetic measurements of the lithium, sodium and potassium phases were performed. It is shown that LiFeP2O7 does not exhibit any abnormal O-O distances contrary to the results obtained by previous authors. A new description of the structure is proposed. The three compounds exhibit an antiferromagnetic transition at TN ≈ 20 K confirming the results obtained by Hagenmüller et al (6). The paramagnetic temperature θp exhibits a regular evolution which can be explained on the basis of Fe-Fe distances and of the number of nearest Fe3+ ions surrounding one iron cation. © 1990.