Studies Of Thin Film Materials For Ultra-high Density Magnetic Recording Head

Generally,magnetic recording system uses compound magnetic head,itincludes two parts:The soft magnetic writing head and the GMR reading head.The performances of the two parts influence the capability of the magneticrecording system directly.In this thesis,our research work have three parts:thefirst part is researching of longitudinally oriented CoCrPt thin film for GMR readhead using; the second part focus on FeCo antiferromagnetic exchange couplingmultilayer; the third part focus on FeCoN soft magnetic thin films.The results areas follows:1.The CoCrPt thin film deposited on CrW underlayer with (200) texturedirectly did not show (11(?)0) longitudinally orientation we expected,but the(0002) perpendicular orientation.When a 3 nm CoCr intermediate layer wasintroduced,we got (11(?)0)longitudinally orientation CoCrPt thin film with Ptatom percent raised from 8.5% to 25%.The CoCr intermediate layer playedan important role to modulate the misfits between the magnetic layer and theunderlayer.2.We built up a three-dimensional micromagnetic model,with carefuldiscussions of the uniaxial crystalline anisotropy and the magnetostriction.Itwas found that the coercivity mechanisms of the CoCrPt thin films aredominated by the magnetostriction effects when the Pt content is more than15 at%.3.We fabricated longitudinally CoCrPt thin film on MgO seed layer and Crunderlayer successfully.4.The addition of N element into FeCo thin film could improve the softmagnetic performance.The magnetic properties of the thin film changedalong with N₂ flux ratio.When the N₂ flux ratio was 10%,it had the bestproperties:4Ï€M_s～20 kG,H_ce～4.5Oe,H_oc～1Oe,H_k～90 Oe.When the N₂flux ratio was 10%,it had the lowest coercivity:H_ce～3Oe,H_ch～0.45 Oe.N₂flux ratio raised from 9% to 18%,FeCoN thin film kept excellent softmagnetic properties,the coercivity on the hard axis kept about 1Oe.5.FeCoN thin films have excellent high frequency performance.When the N₂flux ratio was 10%,we got the highest ferromagnetic resonance frequency as 3.45 GHz.6.FeCo thin film and FeCoN thin film had different magnetization process.FeCo thin film was cluster structure,so the magnetization process was clustermagnetization mode.FeCoN thin film was symmetrical grain structure,thereduction of coercivity of FeCoN thin could attribute to grain size effect.7.We prepared FeCo antiferromagnetic exchange coupling multilayer with Runon-magnetic metallic intermediate layer.When the thickness of Ru layer was0.88 nm,the multilayer had the strongest exchange coupling energy.But themagnetic performance of the multilayer was not good; the coercivity on thehard axis was about 20 Oe.8.We used magnetic force microscope to study the reverse process.As-deposited multilayer divided into some domain and the domain in theupper and bottom layer were corresponding.When the multilayer magnetizedsaturation,all the magnetic moment arrayed along the applied field.Alongwith decreasing and reversing of the applied field,the upper layer appearedmagnetic domain and magnetic moment reversed first.When the all magneticmoment of upper layer except a little nailed by the disfigurement reversed,the bottom layer began to appeared magnetic domain and the magneticmoment reversed then.