Magnetic Long-Range Order and Colossal Magnetoresistance Effect in Double Exchange Ladders
MA Dong-Mei1, ZOU Liang-Jian1,2
1Institute of Solid State Physics, Chinese Academy
of Sciences, Hefei 230031
2National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093
Magnetic Long-Range Order and Colossal Magnetoresistance Effect in Double Exchange Ladders
MA Dong-Mei1;ZOU Liang-Jian1,2
1Institute of Solid State Physics, Chinese Academy
of Sciences, Hefei 230031
2National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093
Abstract： By applying Bogoliubov's inequality to double-exchange (DE)
ladders, we show that the ferromagnetic (FM) order is absent in the new DE systems at finite temperature. The incorporations of Jahn-Teller electron-phonon coupling, orbital degeneracy and on-site Coulomb interaction with the DE interaction do not preserve these orders. The long-wavelength thermal fluctuations of the spins overcome the DEFM correlation and destroy the FM orders. The implication of the absence of FM order on the transport of the DE ladders is discussed.
MA Dong-Mei;ZOU Liang-Jian;. Magnetic Long-Range Order and Colossal Magnetoresistance Effect in Double Exchange Ladders[J]. 中国物理快报, 2001, 18(9): 1264-1267.
MA Dong-Mei, ZOU Liang-Jian,. Magnetic Long-Range Order and Colossal Magnetoresistance Effect in Double Exchange Ladders. Chin. Phys. Lett., 2001, 18(9): 1264-1267.
2001, Vol. 18 
