Structural, magnetic and electrical transport properties of double perovskite Tb₂MnCoO₆

The double perovskite Tb₂MnCoO₆ and two simple perovskites TbMnO₃ and TbCoO₃ were synthesized by a solid sintering reaction method. The Rietveld refinement results based on the x-ray powder diffraction data identified all samples as orthorhombic perovskite structures with space group Pbnm (62). The lattice parameters of Tb₂MnCoO₆ were a = 5.278 (3) Å, b = 5.579 (4) Å, and c = 7.513 (4) Å with a cell volume V = 221.2 (6) ų, Z = 2. Meta-magnetic behavior was observed near 92 K for Tb₂MnCoO₆, which was considered to be related to the coexistence of and competition between the ferromagnetic order and antiferromagnetic order. Temperature-dependent resistance (R-T) was also measured. Compared with TbCoO₃ and TbMnO₃, Tb₂MnCoO₆ is more conductive, with its activation energy reduced from 0.3062 eV for TbCoO₃ (0.2754 eV for TbMnO₃) to 0.1949 eV. The results reported here can assist in understanding the multiferroic physics mechanism of double perovskite materials.