Micro-structure, nano-property and nano-tribological behaviour of the permalloy/copper multilayers

The micro-structure, nano-mechanical behaviour of permalloy/copper magnetic multilayers with various permalloy layer thickness were investigated using scanning probe microscope, X-ray diffraction and nano-mechanical measuring system. Experimental results show that both copper and permalloy layers of these multilayers grow as a meta-stable phase. The multilayers are a good combination of toughness and hardness in the nano-mechanical properties compared with permalloy and copper single layer films. The permalloy layer thickness has a great effect on the micro-tribological behaviour of the permalloy/copper multilayers. When the permalloy layer thickness is reduced to ≤ 1.6 nm, the multilayers exhibit a large critical load, a small scratch width and a low residual scratch depth. When the permalloy layer thickness is reduced from 2.8 nm to 1.2 nm, the surface topography of the multilayers becomes smooth and the particle size decreases from about 120 nm to 25 nm, which will be beneficial to the applications that require a smooth surface.