Low-Temperature Deposition of Co/Pt Film with High-Perpendicular Magnetic Anisotropy by Layer Stacking Sputtering

Abstract

Low-temperature preparation of a Co/Pt layer-stacked film with high-magnetic anisotropy was studied using collimated sputter deposition. Only a trace superlattice line, corresponding to the L1 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> -ordered phase of CoPt, was observed in the X-ray diffraction pattern. However, magnetic properties, exhibited high-saturation magnetization of about 1000 emu/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and large perpendicular magnetic anisotropy, even when the film was deposited at room temperature. For room-temperature deposition, layer-stacked films deposited at a high-Ar pressure of 9.6 Pa exhibited a high coercivity of around 5 kOe and an anisotropy field of around 15 kOe, indicating a high-perpendicular anisotropy of 6.5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> erg/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Deposition at 200 °C increased the anisotropy field up to 20 kOe, indicating a high anisotropy of 1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> erg/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Films deposited without the collimator showed no superlattice line in XRD patterns and exhibited low-saturation magnetization and anisotropy. The cause of the high-perpendicular anisotropy is suggested to be micro ordering in the film.