EFFECT OF ION BOMBARDMENT ON THE PROPERTIES OF MAGNETRON SPUTTERED SAMARIUM COBALT FILMS ON CHROMIUM UNDERLAYERS

摘要

This paper presents the results of our investigations on the deposition and characterization of SmCo films on chromium under layers deposited on single crystal silicon substrates. The effects of low energy ions bombarding the growing films on the composition, surface morphology, (micro) structure, and magnetic properties of the SmCo films have been investigated using Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD) and Superconducting Quantum Interference Device (SQUID) respectively. The films were deposited on a Cr underlayer at 600°C and at a pressure of 10 mTorr with an applied substrate bias varying from 0 to -100 V. The results indicate that as the substrate bias voltage increases, the magnetic properties of the films are enhanced due to smaller grain sizes, better packing density, and improved crystallinity. At a substrate bias voltage of - 60 V both saturation and remnant magnetizations reach maximum values at about 9.30 kG and 7.12 kG, respectively, with an intrinsic coercivity, i{left sub}H_c, of 11.64 kOe. The SmCo films exhibited predominantly Sm_2Co_17 phase (2:17 phase) with (110) orientation. As the substrate bias voltage is further increased, the magnetic properties of the films are deteriorated due to relatively larger grain sizes, decreased density of magnetic phases and poor crystallinity.