The orbital effect on the anomalous magnetism and evolution in La${}_x$Y${}_{1-x}$VO${}_3$($0\le x\le 0.2$) single crystals

Abstract

The orbital effect on the anomalous magnetism and evolution of low La-doping single crystals, La${}_x$Y${}_{1-x}$VO${}_3$ (x = 0, 0.1, and 0.2), has been investigated by applying the X-ray diffraction, specific heat, magnetization and Raman scattering techniques. The larger nearest-neighbor (NN) exchange interaction along c-axis stabilizes the fluctuant G-type orbital ordering (G-OO) which favors the exotic C-type antiferromagnetic order (C-AF). It is found that the NN exchange interaction in ab plane is anisotropy relating to the in plane magnetic anisotropy, which becomes smaller in high La-doped sample. Most interestingly, with increasing the La${}^{3+}$ content the orbital fluctuation and hybridization are decreased which stabilizes the C-OO phase and destabilizes the G-OO phase. Meanwhile, the diamagnetism in the exotic C-AF phase becomes weak and the possible mechanism relates to the change of the competition between the single-ion magnetic anisotropy and the Dzyaloshinsky-Moriya (DM) interaction with increasing x. Finally, the strong spin-orbital coupling has been observed at temperature just above T${}_N$ in La${}_{0.2}$Y${}_{0.8}$VO${}_3$ and a short range spin-orbital correlation is suggested.