Effect of rare-earth doping inRCrSb3(R=La, Pr, Sm, and Gd)

Abstract

We report on the electrical resistivity and magnetic susceptibility of La or Gd doped $R{\mathrm{CrSb}}_{3}$ ($R=\mathrm{La}$, Pr, Sm, and Gd). Single crystals were grown by increasing the nominal dopant by 25%. In general, two magnetic ordering transitions are found, ${T}_{c1}$ is attributed to ferromagnetic ordering of the itinerant Cr sublattice, and, at lower temperatures, ${T}_{c2}$ is attributed to ordering of the localized rare-earth sublattice. Alloying on the rare-earth site varies the de Gennes factor, $\mathrm{DG}={(g\ensuremath{-}1)}^{2}J(J+1)$, and $d{T}_{c1}∕d(\mathrm{DG})=\ensuremath{-}2\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, while $d{T}_{c2}∕d(\mathrm{DG})=5\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. These ordering temperatures are found to converge at ${\mathrm{GdCrSb}}_{3}$, where a single ferrimagnetic transition is found at ${T}_{c2}=86\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ due to an antialignment of the itinerant Cr magnetic sublattice and the localized rare-earth magnetic sublattice. Initially, for $\mathrm{DG}<3.5$, the two magnetic sublattices order in a ferromagnetic ground state, and the paramagnetic Weiss temperature decreases at the same rate as ${T}_{c1}$. But for $\mathrm{DG}>4.5$, the rare-earth magnetic sublattice antialigns with respect to the Cr sublattice, and the Weiss temperature decreases five times as fast. In the region between $(3.5<\mathrm{DG}<4.5)$, a first-order phase transition is found at ${T}_{c2}$.