We have prepared two sets of polycrystalline samples of ${\mathrm{Nd}}_{1-x}{\mathrm{Eu}}_x{\mathrm{CrTiO}}_5$ and ${\mathrm{NdCr}}_{1-y}{\mathrm{Al}}_y{\mathrm{TiO}}_5$, and have measured susceptibility, dielectric constant polarization, and specific heat below 30 K. In both sets, we find that the antiferromagnetic temperature systematically decreases with increasing impurity concentrations. This clearly indicates that not only Cr but also Nd is essential to the magnetic order in the title compound. Such a cooperative behavior of the $4f$ and $3d$ moments is quite unique in comparison with other complex oxides. A possible mechanism of the magnetic order and magnetoelectric response is discussed.

• Received 26 March 2014
• Revised 28 February 2015

DOI:https://doi.org/10.1103/PhysRevB.91.144403