Structure and Physical Properties of Ternary Antimonide YbCrSb₃

Abstract

The ternary rare-earth antimonide YbCrSb3 was prepared by arc-melting of the elements. Its structure was determined by single-crystal X-ray diffraction (Pearson symbol oP20, orthorhombic, space group Pbcm, Z = 4, a = 12.981(3) Å, b = 6.140(1) Å, c = 5.993(1) Å). YbCrSb3 is isostructural to LaCrSb3 and CeCrSb3, and extends the RECrSb3 series (previously known for RE = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy) to the latest rare-earth member yet and to one that is essentially divalent instead of trivalent. Electrical resistivity measurements on single crystals and magnetic susceptibility measurements on powders revealed a magnetic ordering transition at T C = ∼280 K, the highest observed so far in the RECrSb3 series. The isothermal magnetization at 100 K indicated an approach to saturation, but with low values (0.08 μB/mol at 9 T). These results suggest a ferromagnetic or canted antiferromagnetic structure.

Magnetization, resistivity and heat capacity of the anisotropic RVSb3 crystals (R=La–Nd, Sm, Gd–Dy)

“…The only report of rare-earth substitution beyond Dy in RTSb 3 is that reported for YbCrSb 3 . In YbCrSb 3 , however, the ionic radius of Yb ($1.33 Å ), was found to be similar to Sm 3+ (1.27 Å for a coordination number of 9), which hints at divalent Yb 2+ [19]. The reported unit cell volume of YbCrSb 3 is 477.6(2) Å 3 and near to that of SmCrSb 3 and 478.68(10) Å 3 [19].…”

“…Given that variations in stoichiometry have been identified in the RTSb 3 series [11,18,19] and may be a cause for discrepancies in magnetic order [5,[13][14][15][16][17], in this study we start with a detailed structural evaluation of the RVSb 3 (R ¼ La-Nd, Sm, Gd-Dy) flux-grown single crystals. The starting structural parameters were taken from the reported CeTSb 3 (T ¼ Cr, V) structure, Ref.…”

“…A discrepancy for the Curie transition has been found for LaCrSb 3 samples as values in the range of 125-142 K [5,[13][14][15][16][17] are reported, due to various synthetic procedures influencing the stoichiometry of the crystals. For example, in literature the growth of RCrSb 3 crystals in particular includes slow-cooled solidstate reaction [14], arc-melt and annealing of the stoichio- metric mixture [8,19], and also flux [5,6]. The magnetic properties of RCrSb 3 compounds are proven to be sensitive to the degree of Cr site-filling, and there has been evidence for Cr atomic occupancy to as low as 90% in the singlecrystal reports [11,15,18].…”

“…The lower temperature magnetic order has been associated with the presence of either an antiferromagnetic [13,16], canted antiferromagnetic [17] or ferromagnetic [12] spin structure of the R and Cr moments for R ¼ Ce, Pr and Nd. The late members of R ¼ Gd, Tb, Dy and Yb, however, do not display ferromagnetic ordering associated with just the Cr 3+ and for them, the simultaneous ordering of the R-Cr predominates [8,12,16,19]. Compared to RCrSb 3 , RVSb 3 members have only been sparsely studied.…”

Anisotropic magnetic behavior in CeCrSb3

“…They have compared the strong spin correlations observed in LaCrSb 3 with those observed in manganites and suggested that both local moment and itinerant spins coexist in LaCrSb 3 . Recently, Crerar et al [11] have reported that in YbCrSb 3 , Cr orders at 240 K and Yb assumes a charge state close to 2 þ . It appears that correlated ion like Yb influences the magnetic ordering of Cr spins.…”