Thermal stability of Pt/Co multilayered films

Abstract

The thermal stability of Pt/Co multilayered films with various underlayers has been studied by annealing up to 400 °C. In Pt/Co films sputtered on glass or amorphous AlN underlayers, their coercivity and the squareness of magnetic hysteresis loops are degraded by annealing above 300 °C. In contrast, in films sputtered on ZnO or Pt underlayers, the coercivity is remarkably increased by annealing at 300 °C. The film with the ZnO underlayer shows a hysteresis loop with perfect squareness even after annealing at 400 °C. The results of x-ray diffraction indicate that the ZnO underlayer not only enhances the fcc Pt/Co(111) orientation but also prevents the decay of the multilayered structure during annealing. The results of laser microannealing using a conventional disk drive system also indicate that the Pt/Co films with ZnO underlayers have superior resistance to laser damage.