Infrared absorption spectra of La0.67-xPrxCa0.33MnO3 （x= 0, 0.18 and 0.36） are experimentally studied in the temperature range 20 -300K. Absorption peak splitting corresponding to the stretching oscillation of the M...Infrared absorption spectra of La0.67-xPrxCa0.33MnO3 （x= 0, 0.18 and 0.36） are experimentally studied in the temperature range 20 -300K. Absorption peak splitting corresponding to the stretching oscillation of the Mn-O bond, together with a shift of peak position, is observed below the Curie temperature. These features weaken and even disappear as the samples are warmed up to the Curie temperature, which indicates that this anomaly may be a result of phase separation in the compounds.展开更多
The influences of W doping at Mn site on the charge order and spin order were studied by measuring M-T curves, M-H curves and ESR spectra of La0.3Ca0.7Mn1?xWxO3 (x = 0.00, 0.04, 0.08, 0.12, 0.15) system. The results s...The influences of W doping at Mn site on the charge order and spin order were studied by measuring M-T curves, M-H curves and ESR spectra of La0.3Ca0.7Mn1?xWxO3 (x = 0.00, 0.04, 0.08, 0.12, 0.15) system. The results showed that: When 0.00≤ x≤0.08, the system exhibits charge ordering (CO) phase, and its spin order experiences the change of paramagnetism (PM)-charge ordering (CO)-antiferro- magnetism (AFM) with decreasing temperature; when x≥0.12, the charge ordering (CO) phase melts, part of charge ordering (CO)phase remains in the paramagnetism (PM)background, the spin order of the system is mainly paramagnetism (PM), and ferromagnetic (FM) clusters appear at low tem- perature.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos G50225209 and G50271023, the Key Foundation of Education Ministry of China under Grant G02017 and the Natural Science Foundation of Hebei Province under Grant No G503031.
文摘Infrared absorption spectra of La0.67-xPrxCa0.33MnO3 （x= 0, 0.18 and 0.36） are experimentally studied in the temperature range 20 -300K. Absorption peak splitting corresponding to the stretching oscillation of the Mn-O bond, together with a shift of peak position, is observed below the Curie temperature. These features weaken and even disappear as the samples are warmed up to the Curie temperature, which indicates that this anomaly may be a result of phase separation in the compounds.
基金supported by the National Natural Science Foundation of China(Grant No.19934003)the State Key Project of Fundamental Research of China(No.001CB610604)
文摘The influences of W doping at Mn site on the charge order and spin order were studied by measuring M-T curves, M-H curves and ESR spectra of La0.3Ca0.7Mn1?xWxO3 (x = 0.00, 0.04, 0.08, 0.12, 0.15) system. The results showed that: When 0.00≤ x≤0.08, the system exhibits charge ordering (CO) phase, and its spin order experiences the change of paramagnetism (PM)-charge ordering (CO)-antiferro- magnetism (AFM) with decreasing temperature; when x≥0.12, the charge ordering (CO) phase melts, part of charge ordering (CO)phase remains in the paramagnetism (PM)background, the spin order of the system is mainly paramagnetism (PM), and ferromagnetic (FM) clusters appear at low tem- perature.
