Structural phase transition and antiferromagnetic transition of Tb₃RuO₇

Magnetic properties and structural phase transition of terbium ruthenate Tb₃RuO₇ are investigated through magnetic susceptibility, specific heat, high-temperature X-ray diffraction and differential scanning calorimetry measurements. The structural phase transition from space group P2₁nb to Cmcm has been observed at 402 K. Tb₃RuO₇ shows an antiferromagnetic transition at 17 K. In addition, another magnetic anomaly has been found at 10 K. Analysis of the magnetic specific heat for Tb₃RuO₇ indicates that the magnetic transitions at 10 and 17 K are due to the magnetic ordering of Tb³⁺ and Ru⁵⁺ ions, respectively. - Graphical abstract: Temperature dependence of the magnetic specific heat divided by temperature (C_mag/T) and the magnetic entropy (S_mag) for Tb₃RuO₇. Two-step magnetic transition has been observed. - Highlights: • Tb₃RuO₇ shows an antiferromagnetic transition at 17 K. • Specific heat measurements confirmed the occurrence of two-step magnetic transition. • The phase transition from space group P2₁nb to Cmcm has been observed at 402 K