The thin film magnetic disk of the present invention includes a non-metallic substrate having a seed layer deposited on the substrate, an underlayer deposited upon the seed layer composed of a chromium alloy having a relatively high oxygen concentration portion of from 2,000 ppm to 20,000 ppm and preferably approximately 4,000 ppm to 12,000 ppm, followed by a relatively low oxygen concentration portion of from 0-2,000 ppm, and preferably from 500 ppm to 1,500 ppm and a magnetic layer that is deposited upon the underlayer. The underlayer total thickness is in the range of from approximately 250 to approximately 700 with a preferred thickness of approximately 450 , wherein approximately half of the underlayer thickness is the high oxygen concentration portion and half is the low oxygen concentration portion.
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