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Thermoelectric properties of the chemically-doped intermetallic narrow-band semiconductor FeGa 3 are reported. The parent compound shows semiconductor-like behavior with a small band gap (E g = 0.2 eV), a carrier density of ~ 10 18 cm -3 and, a large n-type Seebeck coefficient (S ~ -400 µV/K) at room temperature. Hall effect measurements indicate that chemical doping significantly increases the carrier density, resulting in a metallic state, while the Seebeck coefficient still remains fairly large (~ -150 µV/K). The largest power factor (S 2 /ρ = 62 µW/m K 2 ) was observed for Fe 0.99 Co 0.01 (Ga 0.997 Ge 0.003 ) 3 , and its corresponding figure of merit (ZT = 1.3 × 10 -2 ) at 390 K improved by over a factor of 5 from the pure material.

Raman spectra of LCMO films grown on LAO (001), STO (001), and MgO (001) substrates were studied at different temperatures. The effect of temperature, doping level and strain on Raman spectra are discussed in detail. With decreasing temperature, the changes of Raman spectra are correlated with the disorder-order transition, shuch as: paramagnetism to ferromagnetism, and chargeordering. The strain induced by lattice-substrate mismatch affects the Raman spectra strongly. The mode induced by disorder of oxygen defects is apparently observed in La0.67Ca0.33M nO3 film on STO due to the larger tensile strain. While this mode can not be seen in the Raman spectra for the films on LAO and MgO. A strong unsigned mode at about 690 cm −1 is observed in all films except for La0.67Ca0.33M nO3 film on LAO, which is not observed in bulk sample easily. It suggests that the mode is closely related to the strain.

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