Spin and Orbital Ordering of Y$_{1-x}$La$_x$VO$_3$ (0 $\leq$ x $\leq$ 1)

At lowest temperatures, LaVO$_{3}$ exhibits G-type orbital ordering (OO) and C-type spin ordering (SO), while YVO$_{3}$ has C-type OO and G-type SO. To study the transition of different ground states with the variation of the size of the A-site cation, single-phase Y$_{1-x}$La$_{x}$VO$_{3}$ (0 \textbf{$\le $ }x \textbf{$\le $ }1) samples were melt-grown with the aid of an image furnace. The structural change accompanying the spin and orbital ordering was studied by high-energy, high-resolution x-ray powder diffraction. The temperature dependence of magnetic susceptibility and thermal conductivity was also studied. The results show that C-type OO is stabilized over a wider temperature range as the La content increases in the compositional range 0 \textbf{$\le $ }x \textbf{$\le $ }0.18; Too drops from 200 K for YVO$_{3}$ to 145 K for Y$_{0.82}$La$_{0.18}$VO$_{3}$, while T$_{N}$ decreases slightly from 116 K to 112 K. An abrupt change of the ground state from C-type OO to G-type OO was observed at a critical composition x = 0.20. At x $\ge $ 0.20, all compositions show G-type OO as the ground state and no long-range OO above T$_{N}$ was observed. *Y. Ren, Experimental Facilities Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439