Growth and characterisation of Gd5(SixGe1-x)4 thin film.

We report for the first time successful growth of magnetic thin films containing the Gd5(SixGe1-x)4 phase, which is expected to show giant magnetocaloric properties. The film was deposited by Pulsed Laser Deposition (PLD) on a (001) silicon wafer at 200 °C from a polycrystalline Gd5Si2.09Ge1.91 target prepared by arc melting. PLD was achieved using a femto second laser with a repetition rate of 1 kHz, and a pulse energy of up to 3.5 mJ. The average film thickness was measured to be 400 nm using a Scanning Electron Microscopy and the composition of the film was analyzed using Energy Dispersive Spectroscopy and found to be close to the target composition. X-Ray Diffraction analysis confirmed the presence of Gd5Si2Ge2 monoclinic structure. Magnetic moment vs. magnetic field measurement confirmed that the film was ferromagnetic at a temperature of 200 K. The transition temperature of the film was determined from a plot of magnetic moment vs. temperature. The transition temperature was between 280 and 300 K which is close to the transition temperature of the bulk material. [ABSTRACT FROM AUTHOR]