Structural, magnetic and electrical transport properties in electron-doped La_0.85Hf_0.15MnO₃ epitaxial film

Using a pulsed laser deposition method, the electron-doped La_0.85Hf_0.15MnO₃ (LHMO) film with the thickness of 90 nm was epitaxially grown on LaAlO₃ (001) single crystal substrate. The structural, magnetic and electrical transport properties of the film have been studied comprehensively. The X-ray diffraction patterns confirm that LHMO film is of single phase, good quality and c axis orientation. The film undergoes a ferromagnetic-like ordering to paramagnetic states at T_C =280 K. Moreover, a spin glass behavior observed in the film may be attributed to the strain effects. Using the percolation theory, we have analyzed the resistivity data ρ (T) of the film and given an excellent fit in the whole temperature range. Particularly, large temperature coefficient of resistance of 11.27% K^{- 1} has been discovered near sub-room-temperature, indicating that LHMO film could be useful for bolometric applications. (orig.)