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GdMnO$_3$ came to the attention of the scientists due to the discovery of multiferroicity in this compound. It crystallizes in the orthorhombically distorted perovskite structure; space group $Pnma$; Gd ions are located on $4c$; Mn ions on $4b$ and oxygen anions are located on $4c$ and $8d$ crystallographic sites. The compound orders into antiferromagnetic phase below $T_N\sim 40$ K [1] and then undergoes order-to-order magnetic phase transition into low temperature canted magnetic phase at $T_{lock}$ ($\sim 20$ K). The opened question is, if the magnetism and multiferroicity can be tuned in order to increase application potential of this material. In our previous paper we reported on Mn-Fe substitution [2] and our present study is focused on Mn-Ti substitution.
GdMn$_{1-x}$Ti$_x$O$_3$ compounds were synthetized by the floating zone method and structural analysis of final compounds was carried out through Rietveld refinement. It was found that the samples up to $x=0.1$ are single-phase with the crystal structure related to GdMnO$_3$ parent compound. For $x>0.1$, the impurity phases were detected which restricts the study of this system to low Ti concentrations. The Ti substitution shifts the lattice parameters from $a=5.852(2)$ Å; $b=7.423(3)$ Å and $c=5.310(2)$ Å to $a=5.837(1)$ Å; $b=7.484(1)$ Å; $c=5.329(1)$ Å. The Neel temperature $T_N$ is not visible on magnetization measurements, however, from the combination of zero-field-cooled; field-cooled magnetization data and hysteresis loops $M$(B) we concluded the decrease of $T_N$ from $42$ K ($x=0$) to roughly $30$ K ($x=0.1$). $T_{lock}$ has been also shifted from $\sim 20$ K ($x=0$) to $\sim 2$ K ($x=0.1$). In the temperature interval $T_{lock} In the contribution, we present a comprehensive study of GdMn$_{1-x}$Ti$_x$O$_3$ ($0\leq x\leq0.1$) substitutional system. To ensure a thorough understanding, we compare and discuss our results with results obtained by other groups for the concentrations, for which the data are available. This publication is the result of the project implementation: VEGA 2/0004/25. [1] N. Pavan Kumar et al., “Specific heat and magnetization studies ofRMnO3(R=Sm, Eu, Gd, Tb and Dy) multiferroics,” Physica Scripta, vol. 83, no. 4. IOP Publishing, p. 045701, Mar. 08, 2011. https://doi.org/10.1088/0031-8949/83/04/045701Acknowledgements
References
[2] M. Mihalik Jr. et al., “Magnetism of GdMn1-xFexO3 (0≤x≤1) Nanoparticles,” Acta Physica Polonica A, vol. 137, no. 5. Institute of Physics, Polish Academy of Sciences, pp. 993–996, May 2020. https://doi.org/10.12693/aphyspola.137.993
