Magnetic and recording properties of CoCrPtTa thin film media with CrW underlayer

CoCrPtTa thin film media using Cr as an underlayer has been developed as a candidate for future high density longitudinal recording. In an effort to r educe the lattice mismatch between the Cr underlayer and the magnetic layer , the Cr underlayer has been doped with various elements. In this work the effect of adding W-x (x = 10 and 15 at. %) to the Cr underlayer on the magn etic, crystallographic, and recording properties are reported. CrW10(Cr90W1 0) underlayer produced about 400 Oe higher coercivity and higher S* at Mrt approximate to 0.60 memu/cm(2) compared to the Cr underlayer. Also at 240 k fci recording density for CoCrPtTa/CrW10 media the normalized media noise w as similar and signal-to-noise ratio was about 2 dB higher compared to the CoCrPtTa/Cr media. For the CrW15(Cr85W15) underlayer at Mrt approximate to 0.60 memu/cm(2) the coercivity was about 300 Oe higher with S* = 0.88, but the normalized media noise was also higher than the CoCrPtTa/Cr media. The x-ray diffraction data suggest better lattice match between the CoCrPtTa/Cr W10 media due to the addition of W to the Cr underlayer compared to the CoC rPtTa/Cr media. The magnetic and recording properties are correlated to the crystallographic properties of the CoCrPtTa/CrW thin film media. (C) 1999 American Institute of Physics. [S0021-8979(99)69108-3].