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Magneto-transport characteristics of La1.4Ca1.6Mn2O7 thin film deposited by spray pyrolysis

P. K. Siwach·H. K. Singh·O. N. Srivastava
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Abstract

Polycrystalline thin films of double layer manganite La_1.4Ca_1.6Mn_2O_7 (DLCMO) have been deposited by nebulized spray pyrolysis on single crystal LaAlO_3 substrates. These single phase films having grain size in the range 70-100 nm exhibit ferromagnetic transition at T_C ~ 107K. The short range ferromagnetic ordering due to in plane spin coherence is evidenced to occur at a higher temperature around 225 K. Insulator/semiconductor to metal transition occurs at a lower temperature T_P ~ 55K. The transport mechanism above T_C is of Mott`s variable range hopping type. Below T_C the current-voltage characteristics show non-linear behaviour that becomes stronger with decreasing temperature. At low temperatures below T_CA ~ 30K a magnetically frustrated spin canted state is observed. The DLCMO films exhibit resonable low field magnetoresistance and at 77K the magnetoresistance ratio is ~ 5% at 0.6 kOe and \~ 13% at 3 kOe.

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P. K. Siwach, H. K. Singh, O. N. Srivastava. 2005-05-17. Magneto-transport characteristics of La1.4Ca1.6Mn2O7 thin film deposited by spray pyrolysis. https://doi.org/10.1088/0022-3727%2F39%2F17%2F003

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