Effect Of Manganese Doping On The Magnetization Of LuCrO₃

RCrO₃ with perovskite-typed structure and its dopants have been widely studied due to their abundant physical diagrams,such as magnetization reversal,exchange bias,spin-reorientation,multiple magnetic phases.It has been found experimentally that many rare-earth orthochromic RCrO₃s show magnetization reversal phenomenon,but this phenomenon has not been confirmed on LuCrO₃.In addition,several explanations of magnetization reversal on Mn-doped RCrO₃ ignored the influence of the electronic structure of ions.In order to study the effect of Mn doping on the magnetic properties of LuCrO₃ and the electronic structure of related ions,a series of samples of LuCr_1-xMn_xO₃?x=0,0.1,0.2,0.3?were prepared by high temperature solid-state reaction and studied in terms of power X-ray diffraction,magnetic properties and soft X-ray absorption spectroscopy.The crystal structure,magnetic properties and electronic structures of LuCr_1-xMn_xO₃?x=0,0.1,0.2,and 0.3?series samples were systematically investigated.The crystal structure of the Mn-doped LuCrO₃ samples is orthorhombic structure with Pbnm,consistent with the pristine LuCrO₃.Synchrotron radiation soft X-ray absorption spectroscopy of Mn 2p,Cr 2p and O 1s core levels show that Cr ion is trivalent and its valence state does not change with doping.However,the valence state of Mn ions for samples with x=0.1 and 0.3 is mainly in Mn²⁺while it is dominated by Mn³⁺for the sample x=0.2.This leads to the diversely unoccupied 3d states of transitional metal ions,which hybridized with O 2p levels.The energy diagram of each transitional metal ions in our samples were provided.More interesting,magnetic data shows the negative magnetization in zero-field cooling M_ZFC?T?curve below T_N.And the evolution of M_FC?T?and M_ZFC?T?curves coming to converge and intersect with each other was caused by Mn doping.Also,multiple magnetic phases with a new magnetic phase transition at 30 K were induced by the effect of Mn doping.Those results demonstrate that the antiferromagnetic coupling of Mn²⁺being antiparallel with spin moment of Cr³⁺is favor of the magnetization reversal while the ferromagnetic coupling of Mn³⁺overcomes the Cr³⁺ions ordering and destroys the magnetization reversal.