Magneto-structural Imprints in Eu-Substituted NdCrO\({_3}\) Perovskites

The chemical pressure-induced magneto-structural changes were investigated in Nd \({_{1-x}}\) ${}_{1-x}$ Eu \({_{x}}\) ${}_x$ CrO \({_3}\) ${}_3$ with \({0.2 \le x \le 1.0}\) $0.2\le x\le 1.0$ compounds. The magnetic study shows the decrease of antiferromagnetic transition temperature ( \(T_\textrm{N}\) $T_{\text{N}}$ ) \(\sim\) $\sim$ 220.7 K (x = 0.2) to 182.5 K (x = 1.0) due to the modification of Cr-Cr interaction. The spin-reorientation transition ( \(T _\textrm{SR}\) $T_{\text{SR}}$ ) exhibits for all samples except x = 1.0 with a decrease from \(\sim\) $\sim$ 40.1 K (x = 0.2) to 13.3 K (x = 0.9). We observed the exchange bias (EB) effect and the EB field decreases with increasing Eu content. The chemical pressure boundary at x = 0.5 is marked and the lattice softens on both sides of this substitution. The magnetoelastic coupling below \(T_\textrm{N}\) $T_{\text{N}}$ is revealed by the temperature dependence of the lattice parameters, Cr-O lengths, Cr-O-Cr angles, and Nd/Eu positions for \(x < 0.5\) $x<0.5$ samples. We have reported the electron density distribution using the maximum entropy method for the first time in the Nd \({_{1-x}}\) ${}_{1-x}$ Eu \({_{x}}\) ${}_x$ CrO \({_3}\) ${}_3$ compound. Interestingly, we found a structural reorientation around \(\sim\) $\sim$ 80 K between \(T_\textrm{N}\) $T_{\text{N}}$ and \(T _\textrm{SR}\) $T_{\text{SR}}$ from a centrosymmetric structure (Pnma) with unstable electron density to a stable noncentrosymmetric \((Pna2_1)\) $(Pna{2}_1)$ structure.