Optical study ofPr1−xCaxMnO3

Resonant x-ray diffraction of the magnetoresistant perovskitePr0.6Ca0.4MnOGrenier1, Hill2, Gibbs3 et al. 2004Phys. Rev. BSelf Cite1025711View full textAdd to dashboardCite

“…The COO phase in Pr 0.6 Ca 0.4 MnO 3 is evidenced by a sudden decrease in the magnetic susceptibility, an increase in the resistivity at T COO > T N [23,24] and by the appearance of superstructure Bragg reflections which indicate a doubling of the unit cell. These reflections also disappear when the magnetic field drives the compound into the metallic state [14].…”

Control of the electronic phase of a manganite by mode-selective vibrational excitation

“…[2][3][15][16][17][18] In the pump-probe spectroscopy studies, Pr 0. to the formation of a pseudo plasma edge in the metallic state. 12 Our observation of the ultrafast formation of a metallic-like reflectivity spectrum following 17 m pump excitation provides the first evidence that the metallic state is formed promptly (within the 300 fs experimental resolution) via direct vibrational excitation, 20 and that this state persists for 100's of picoseconds. Magneto-optic Kerr effect measurements following mid-infrared excitation will be important in the future to establish whether this insulator-to-metal transition is synonymous with an antiferromagnetic-to-ferromagnetic phase transformation, as would be expected for a magnetoresistive manganite where metallicity is associated with ferromagnetism through a double-exchange mechanism.…”

“…Figure 1(b) shows the low-temperature optical conductivity spectrum of Pr 0.7 Ca 0.3 MnO 3 with three dominant phonon modes (23,42, and 71 meV) 12 corresponding to the three (F 2u ) infrared active vibrational modes of a cubic perovskite. 13 The two highest frequency vibrations are assigned to the Mn-O-Mn bending mode and the Mn-O stretching mode respectively.…”

Charge, orbital, and magnetic order inNd0.5Ca0.5MnO3<

“…Such a behavior is very sensitive to stoichiometry. In P r 0.6 Ca 0.4 MnO 3 [9], [11], as well as in Nd 0.6 Ca 0.4 MnO 3 [12], the anomaly at T CO persists while the signature of T N is quite visible. What is the exact nature of the phase when T N < T < T CO ?…”