Magnetization spin reversal and neutron diffraction study of polycrystalline Tb0.55Sr0.45MnO3

We have investigated the structural and magnetic phase transitions in Sr doped polycrystalline Tb0.55Sr0.45MnO3, using temperature-dependent high-resolution neutron powder diffraction in the HRPT diffractometer at PSI to address the origin of magnetization reversal at low temperature. The solid solution Tb0.55Sr0.45MnO3 crystallizes in O′ type orthorhombic structure having the Pnma symmetry. The substitution of the divalent cation of Sr2+ at the site of Tb3+ dilutes the Mn–Tb interaction and affects the magnetic structure, which was observed by the field and temperature-dependent dc magnetization and neutron diffraction study. The temperature-dependent zero field-cooled and field cooled dc magnetization study reveals the indication of spin reversal phenomena, which is the nature of canted antiferromagnetic or ferrimagnetic transition at 100 Oe because of Mn–Mn sub-lattices interaction below 65 K. By increasing the applied magnetic field up to 20 kOe, a weak ferromagnetic type of behaviour is observed. The field-dependent magnetization shows weak coercivity due to the canted spin structure at low temperatures. The low-temperature neutron diffraction study of polycrystalline Tb0.55Sr0.45MnO3 reveals the non-collinear canted antiferromagnetic structure due to Tb ordering at 1.5 K, which turns into a non-collinear ferromagnetic structure along with spin canting followed by the spin reversal phenomena at 25 K. •Structural analysis reveals the O′ type of orthorhombic lattice distortion in polycrystalline Tb0.55Sr0.45MnO3.•Cation doping of Sr2+ doping induces a mixed-valent state of Mn3+/Mn4+ and dilutes the magnetic interactions of Tb3+ ion.•Neutron diffraction study of polycrystalline Tb0.55Sr0.45MnO3 is observed using a temperature-dependent HRPT diffractometer @ PSI.•dc magnetization and magnetic structure study reveal the indication of spin reversal phenomena due to Mn–Mn sub-lattice interaction.•The spin reversal transition from non-collinear canted AFM structure to non-collinear canted FM phase transition is observed by NPD.