Research On Magnetic Record Medium Materials

With the rapid development of information society, people have to deal with the growing amount of information. Hard disk plays a very important role in magnetic recording medium. As the constant upgrade of recording density, lots of adverse effects become to the disadvantage on the increase of recording density about longitudinal recording mode more obvious. These effects such as the superparamagnetic effect due to the decrease of particle size can't be neglected. It demands breakthrough not only on material but also on the craft. L10FePt alloy has become the research hotspot. This thesis sets about improving the ferromagnetism of FePt alloy. We study respectively on Bi/FePt/C magnetic thin films used as longitudinal magnetic recording materials and MgO/FePt/Au magnetic thin films used as perpendicular recording material.First we do research on series Bi/FePt/C samples preparated by magnetron sputtering, investigate the microstructure and magnetic characteristics paralle to the films surface for the prepared and annealled samples. During the sputtering process,we discover that trace of Bi atoms diffussion into the boundary of magnetic crystal grains. This restrains the growth of magnetic crystal grains, reduces the interaction of exchange coupling, debase the interfacial energy. The process of diffussion leads to lattice mismatch in magnetosphere that as the pinning center to promote the formation of ordered phase. This condition affects the characteristics of the thin films including neat surface morphology, big coercive force, low background acoustic noise.Then we investigate the influence of Au layer on the ordered degree and perpendicular orientation of the MgO/FePt/Au thin films by doping Au mesosphere with different thickness into the middle of the MgO substrates. We measure the microstructure and magnetic characteristics of the samples using XRD and VSM and find that MgO substrate deposited at room temperature has (100) orientation. This substrate induces (200) preferential of Au mesosphere presents leading FePt magnetic layer with perfect (001) texture.