Kondo lattice behavior in the ordered dilute magnetic semiconductorYb14−xLaxMnSb11

Abstract

We report Hall, magnetic, heat capacity and doping studies from single crystals of Yb14MnSb11 and Yb13.3La0.7MnSb11. These heavily doped semiconducting compounds are ferromagnetic below 53 K and 39 K respectively. The renormalization of the carrier mass from 2me near room temperature to 15me at 5 K , plus the magnetic evidence for partial screening of the Mn magnetic moments suggest that these compounds represent rare examples of an underscreened Kondo lattice with TK ≈ 350 K.

Magnetic and structural effects of partial Ce substitution in Y b14MnSb11

“…Since Yb 14 MnSb 11 magnetically orders through a RKKY coupling mechanism, this is an expected effect of decreasing carrier concentration. The ferromagnetic ordering temperature T C , presented in Table I, reaches a minimum of 39 K, the same as that observed for Yb 13.3 La 0.7 MnSb 11 , 12 starting with x = 0.45, while higher values of x show no further decrease in T C . This happens at the point at which Ce starts filling the Yb(4) site, and additional low temperature studies are needed to gain insight into the magnetic ordering mechanism.…”

“…The amount of Ce that can be incorporated into Yb 14−x Ce x MnSb 11 via the Sn flux synthesis is limited to approximately 0.6 Ce per formula unit, similar to the amounts of La and Tm, which have been incorporated into the structure, with maxima of about 0.7 La and 0.5 Tm per formula unit. 12,19 The structure of each crystal magnetically characterized was confirmed using single crystal XRD to be the expected Yb 14 MnSb 11 structure type in the I4 1 /acd space group. Figure 2(c) shows that the lattice parameters increase with increasing Ce content while maintaining a constant c/a ratio.…”

“…C 2015 Author(s Magnetic measurements on the La-doped material show a depression of the magnetic ordering temperature, which is to be expected since the strength of RKKY coupling depends on carrier concentration. 12 The previous work on the La and Tm solid solutions shows that only a limited amount of rare earth can be substituted in the system. 12,18,19 Ce was chosen to substitute for Yb because it will likely substitute as Ce 3+ , which has an unpaired 4 f 1 electron and commonly participates in Kondo interactions.…”

“…12 The previous work on the La and Tm solid solutions shows that only a limited amount of rare earth can be substituted in the system. 12,18,19 Ce was chosen to substitute for Yb because it will likely substitute as Ce 3+ , which has an unpaired 4 f 1 electron and commonly participates in Kondo interactions. Ce substitution is expected to increase the magnetic moment of the Yb 14 MnSb 11 , partially not only due to unpaired f electron associated with Ce 3+ but also by reducing the screening of Mn moments due to the additional electron introduced by Ce substitution occupying the tetrahedron's associated hole.…”

Synthesis, structure, magnetism, and high temperature thermoelectric properties of Ge doped Yb14MnSb11

“…This is quite different from the cation doped Yb 14 MnSb 11 (La, Gd) where small amounts of the dopants made significant effects reflected in the magnetic data. 23, 26 Fig . 5 shows the magnetization vs. temperature and the inverse susceptibility (inset) for the Ge doped compound.…”