Role of processing parameters on the morphology and magnetic properties of Tb–Fe–Co thin films

• Co addition aids achieving room temperature ferromagnetism in Tb–Fe films.
• Compensation temperature observed in amorphous Tb–Fe–Co films.
• Films processed at lower argon gas pressures exhibit strong ferromagnetism.
• Films deposited at higher gas pressures exhibit sperimagnetic behavior.

The effect of processing parameters such as argon gas pressure (5, 10 and 15 mTorr) and sputtering power (50 and 100 W) on the structure, microstructure and magnetic properties of dc magnetron sputtered Tb–Fe–Co films was investigated. X-ray diffraction studies indicate that all the films were found to be amorphous in nature irrespective of the deposition conditions. The increase in sputtering gas pressure and power was found to deplete the transition metal content in the films. Room temperature ferromagnetism accompanied with low coercivity (20 Oe) and low saturation magnetic field has been achieved for the film grown at 5 mTorr gas pressure and 50 W sputtering power. The microstructure of Tb–Fe–Co films showed the presence of islands, whose size increased with increasing sputtering power and argon gas pressure. Magnetization studies indicated that all the films were magnetically ordered up to room temperature. A compensation temperature was observed for the films grown at higher gas pressure and sputtering power. Annealing of the films did not result in any crystallization and as a consequence the magnetic properties were found to remain unaltered.