Anomalous ferromagnetic spin fluctuations in an antiferromagnetic   insulator Pr_{1-x}Ca_{x}MnO_{3}
  The high temperature paramagnetic state in an antiferromagnetic (AFM) insulator Pr_{1-x}Ca_{x}MnO_{3} is characterized by the ferromagnetic (FM) spin fluctuations with an anomalously small energy scale. The FM fluctuations show a precipitous decrease of the intensity at the charge ordering temperature T_{CO}, but persist below T_{CO}, and vanish at the AFM transition temperature T_{N}. These results demonstrate the importance of the spin ordering for the complete switching of the FM fluctuation in doped manganites. 
R. Kajimoto, T. Kakeshita, Y. Oohara, H. Yoshizawa, Y. Tomioka and Y.   Tokura