On the magnetism and electronic behavior of TbTiO3: A comprehensive study for cryogenic applications

Meeting the requirements of low-temperature magnetocaloric cooling necessitates materials with attractive magnetic properties. This has led to a growing interest in developing strongly correlated materials such as ortho-perovskite oxides RMO₃ (R = rare earth, M = transition metal). In this study, Density Functional Theory (DFT) and Monte Carlo simulations (MCs) were used to systematically investigate the structural, electronic, magnetic, and magnetocaloric properties of TbTiO₃ compound. In particular, TbTiO₃ is found to be a ferromagnetic compound exhibiting a semiconducting behavior with a band gap of 0.48 eV. Additionally, a ferromagnetic (Tb-Ti) interaction significantly exceeds the other interactions in TbTiO₃ based on the Ising model, the magnetic contributions of Tb and Ti atoms within TbTiO₃, and the magnetocrystalline anisotropy energies are elucidated. Interestingly, TbTiO₃ exhibits two second-order magnetic transitions at T_s = 17 K and T_c = 55 K. These latter are associated with a significant magnetic entropy change (−ΔS_mag), featuring peak values of 10.83 J/kg K and 6.3 J/kg K, as well as adiabatic temperature changes of 6.83 K and 3.5 K, under 5 T at T_s, and T_c, respectively. Indeed, TbTiO₃ achieves an impressive refrigerant capacity of 704.48 J/kg, due to the large operating temperature range, making TbTiO₃ suitable as an active element in low-temperature magnetic refrigerators.