Three members of the perovskite family $R\mathrm{F}{\mathrm{e}}_{0.5}\mathrm{C}{\mathrm{r}}_{0.5}{\mathrm{O}}_3$ ($R=\mathrm{Lu},\mathrm{Yb}$, and Tm) have been synthesized and characterized. A systematic study of the crystal and magnetic structures was performed by neutron powder diffraction combined with magnetization measurements. All these compounds crystallize in a Pbnm orthorhombic unit cell and they are already antiferromagnetic at room temperature. The study of the magnetic structure vs temperature showed the occurrence of a progressive spin reorientation from ${\mathrm{\Gamma }}_4^{\text{TM}}$ to ${\mathrm{\Gamma }}_2^{\text{TM}}$ for the transition metal sublattice, and in the Tm-based sample, a long-range magnetic order of the $\mathrm{T}{\mathrm{m}}^{3+}$ sublattice was found $\left({\mathrm{\Gamma }}_8^R\right)$. These results are in excellent agreement with the magnetic susceptibility measurements. No spin reorientation is observed in the Lu-based sample for which a magnetization reversal at a compensation temperature $T_{\mathrm{comp}}=225\mathrm{K}$ was detected. A clear magnetostrictive effect was observed in the samples with $R=\mathrm{Yb}$ and Tm associated with a negative thermal expansion and was assigned to a magnetoelastic effect produced by repulsion between the magnetic moments of neighboring transition metal ions.

• Received 6 November 2015
• Revised 12 September 2016

DOI:https://doi.org/10.1103/PhysRevB.94.134402