Suppressing low-frequency noise in La0.8Ba0.2MnO3 films by a simple method of controlling film thickness

Thin films of La0.8Ba0.2MnO3, whose temperature coefficients of resistance become high at around room temperature, were grown on SrTiO3(100) substrates by conventional pulsed-laser deposition, and the excess low-frequency electrical noise was measured in an ambient magnetic field. The two-probe noise spectra observed at room temperature can be described by the Hooge’s empirical relation. The Hooge parameter normalized by carrier density (γ∕n) was strongly dependent on the sample thickness, and films less than 50nm thick exhibited much lower noise than thicker films. This demonstrated dependence on thickness provides a simple and easy means of suppressing the noise in manganite thin films using conventional techniques.