Magnetic and structural effects of partial Ce substitution in Yb14MnSb11

Abstract

Single crystals of Yb14-xCexMnSb11 were grown from tin metal as a flux solvent with a maximum Ce incorporation of 0.6. The phases with x ∼ 0.1-0.6 crystallize in the tetragonal Ca14AlSb11 structure type with I41/acd space group. In this structure type, there are 4 crystallographically unique Yb sites and the structure can be described according to the Zintl concept as containing 14Yb2+ + [MnSb4]9- + [Sb3]7- + 4Sb3-. For x > 0.3, Ce is incorporated on specific Yb sites in the structure as a function of x, initially at x = 0.3 on the Yb(2) site followed by Yb(4) at higher values of x. These sites have the largest volume as indicated by Hirshfeld surface analysis of chemical bonding. As Ce content is increased, the ferromagnetic ordering temperatures decrease and effective paramagnetic moments increase. The magnetic ordering temperatures decrease from the undoped TC of 50 K until x ∼ 0.4, where the lowest TC of 39 K is reached. As the additional electron introduced by Ce3+ fills the hole associated with [MnSb4]9-, the screening of the Mn moments is reduced. This leads to an increase in overall moment attributed to Mn in addition to the moment from the Ce3+ f electron. Increasing Ce content also leads to an increase in electrical resistivity, an expected effect from reducing the carrier concentration.