No abstract

FeF, and Mn2Sb207 elhi it 7 ex ibit long-range magnetic order at 1 5.5 netic susceptibility data fo th or ese compounds show a stron de r er at .5 and 13 K, respectively. B lk u magations from a Curie-Wei -1 b h ssaw e avior far above the orderin tern a s rong ependence on sample histor d d y an evlbuted to short-range order e or ering temperatures. These effects a tt ' d b h }1' hl fr tdl tti g a e attlce of corner-sharin tetr above T eu ronl raction data given clear evidence T, . Fo ' 1 i ofth d t ' ld F in erms o spin-spin corr 1 t' e a ions out to the f u ion unction g o oo to s e serve strong antiferromagnetic first-nei hbor n ir -neighbor, spin-spin correlations.ig or, and ferromagnetic second-