The Enhanced Magnetic Performances of Sm-doped GdMnO 3 By Optimizing Vacancy Defects and Valence States of Mn

The role of Sm doping on the structure, vacancy characteristics, valence states of the constituent elements, and magnetic performances of Gd 1- x Sm x MnO 3 ( x = 0.00–0.20) ceramics synthesized using the solid-state reaction method is discussed. The X-ray diffraction and Raman spectroscopy results revealed that the orthorhombic perovskite structure with a single phase was formed in all Gd 1- x Sm x MnO 3 ceramics, and the addition of Sm ions induced lattice deformation. The X-ray photoelectron spectroscopy and positron annihilation spectroscopy results showed that the vacancy concentration and Mn 4+ content in Gd 1- x Sm x MnO 3 samples initially increased and subsequently decreased as the Sm doping concentration was increased. The magnetic property measurements revealed that Sm doping had a significant impact on the low temperature magnetic ordering of Gd 3+ ions, magnetic transition temperatures, and magnetization. From the correlation study between structure and properties, it could be concluded that the development of magnetic characteristics was closely related to the cation vacancies concentration and the creation of Mn 4+ in Gd 1- x Sm x MnO 3 samples.