Hf3Fe4Sn4 and Hf9Fe4−xSn10+x: Two stannide intermetallics with low-dimensional iron sublattices

Abstract

This article reports two new Hf-rich intermetallics synthesized using Sn flux: Hf3Fe4Sn4 and Hf9Fe4−xSn10+x. Hf3Fe4Sn4 adopts an ordered variant the Hf3Cu8 structure type in orthorhombic space group Pnma with unit cell edges of a=8.1143(5)Å, b=8.8466(5)Å, and c=10.6069(6)Å. Hf9Fe4−xSn10+x, on the other hand, adopts a new structure type in Cmc21 with unit cell edges of a=5.6458(3)Å, b=35.796(2)Å, and c=8.88725(9)Å for x=0. It exhibits a small amount of phase width in which Sn substitutes on one of the Fe sites. Both structures are fully three-dimensional and are characterized by pseudo one- and two-dimensional networks of Fe–Fe homoatomic bonding. Hf9Fe4−xSn10+x exhibits antiferromagnetic order at TN=46(2)K and its electrical transport behavior indicates that it is a normal metal with phonon-dictated resistivity. Hf3Fe4Sn4 is also an antiferromagnet with a rather high ordering temperature of TN=373(5)K. Single crystal resistivity measurements indicate that Hf3Fe4Sn4 behaves as a Fermi liquid at low temperatures, indicating strong electron correlation.