Terahertz (THz) radiation with its spectrum extending up to 1 THz has been
observed by an illumination of femtosecond optical pulses to optical switch
ing devices fabricated on magnetoresistive manganite thin films; Pr0.7Ca0.3
MnO3. The THz radiation strongly depends on temperature T and its T trend r
everses sign across charge-orbital and spin-ordering T. (C) 2001 American I
nstitute of Physics.