Effects of Ru and Ag cap layers on microstructure and magnetic properties of FePt ultrathin films

Table 1 The melting point and CTE stress of the FePt layer and the cap layer

Bilayer	Cap layer material	Melting point (°C)	CTE (ppm/K)	Thermal stress [ 21 ] (GPa) at 500°C	References
FePt/Ru	Ru	2,250	<6.5	−0.54	[23]
FePt/Ag	Ag	961	19.2	1.17	[4,24]
FePt	Without	>1,519	10.5	0	[21]
Substrate	SiO₂	1,670	0.5	−1.34	[25]