Doping-Induced Phase Transitions in Polycrystalline La0.49Sr0.51(Mn1-xNbx)O3
LIU Wen-Jun1,2, SHU Qi-Qing1,2, MA Xiao-Cui1,2, S. M. Bhagat3, S. E. Lofland3, I. O. Troyanchuk4
1Department of Material Science and Engineering, School of Science, Shenzhen University, Shenzhen 518060
2Shenzhen Key Laboratory of Special Functional Materials, Shenzhen University, Shenzhen 518060
3Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA
4Institute of Solid State Physics, National Academy of Sciences of Belarus, P. Brovki Street 17, Minsk 220072, Belarus
Doping-Induced Phase Transitions in Polycrystalline La0.49Sr0.51(Mn1-xNbx)O3
LIU Wen-Jun1,2;SHU Qi-Qing1,2;MA Xiao-Cui1,2;S. M. Bhagat3;S. E. Lofland3;I. O. Troyanchuk4
1Department of Material Science and Engineering, School of Science, Shenzhen University, Shenzhen 518060
2Shenzhen Key Laboratory of Special Functional Materials, Shenzhen University, Shenzhen 518060
3Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA
4Institute of Solid State Physics, National Academy of Sciences of Belarus, P. Brovki Street 17, Minsk 220072, Belarus
Abstract： Observations of temperature dependences of ac susceptibility Xac, resistivity (ρ) and dc magnetization M for polycrystalline La0.49Sr0.51(Mn1-xNbx)O3 (x = 0, 0.05, 0.15, and 0.25) show that due to substitution of Mn4+ by diamagnetic Nb5+, there appear to be (i) the decrease of Xac as T> TN, (ii) the occurrence of a maximum (insulator-metal-like transition) for ρ near TC, (iii) the decline of M as x>0.05, and (iv) the lowering of TC. The results might be ascribed to: (i) the rearrangement of Mn3+ and Mn4+ ions, (ii) the decrease of the number of Mn3+ and Mn4+ pairs involved in double exchange interaction, (iii) the delocalization of the electrons and holes, (iv) the reduction of the randomness of the delocalized carrier scattering by thermal spin fluctuation due to magnetic ordering, and (v) the compensation effect of Nb5+ ions for Sr2+ ions.
LIU Wen-Jun;SHU Qi-Qing;MA Xiao-Cui;S. M. Bhagat;S. E. Lofland;I. O. Troyanchuk. Doping-Induced Phase Transitions in Polycrystalline La0.49Sr0.51(Mn1-xNbx)O3[J]. 中国物理快报, 2005, 22(4): 938-941.
LIU Wen-Jun, SHU Qi-Qing, MA Xiao-Cui, S. M. Bhagat, S. E. Lofland, I. O. Troyanchuk. Doping-Induced Phase Transitions in Polycrystalline La0.49Sr0.51(Mn1-xNbx)O3. Chin. Phys. Lett., 2005, 22(4): 938-941.
2005, Vol. 22 
