Revisiting the fascinating properties of EuTiO3 and its mixed crystals with SrTiO3: Possible candidates for novel functionalities

• EuTiO3 is an almost multiferroic compound.
• At TN=5.7 K, it becomes a G-type antiferromagnet.
• At TS=282 K, its cubic structure transforms to tetragonal.
• Fluctuating magnetism occurs below TS.
• Its mixed crystals with SrTiO3 display a complicated and rich phase diagram.

The research in perovskite oxides is ever increasing since their discovery in 1945. The number of compounds with this rather simple structure is growing continuously since then and fascinating properties ranging from magnetic via dielectric and superconducting have been reported for them. While an extreme research activity has been devoted to SrTiO3 from its discovery on, its analog EuTiO3 has attracted rather little interest until recently. In this review we concentrate on the recent results from studies of this perovskite and its mixed crystals with SrTiO3 and demonstrate that novel interesting properties are related to it. Specifically we provide evidence for the existence of hybrid-paramagnon–phonon coupling at elevated temperatures and its manifestations in bulk sensitive experiments. In addition, the phase diagram of the mixed crystal series is presented where pressure and temperature effects are included.