Improvement of magnetic properties of nanodimensional FePt films for ultrahigh density magnetic recording and information storage

Keywords
New substances and materials

Description
Formation of stable nanoscaled magnetic L10-FePt(FCT) films with enhanced thermal stability, controlled orientation of grain, easy magnetization axis and coercitivity at creation of magnetic recording medium with ultrahigh recording density ( 1Tb/cm2) and information storage.

Innovative aspect and main advantages:
At present recording density and information storage by magnetic method is 10-15 Gbit/cm2.
It is developed new approach to diffusion formation of stable nanoscaled magnetic-hard FePt films with chemically ordered L10(FePt)FCТ phase at use of additional layers of alloying elements (Ag, Au, Cu) with low surface energy. Interface energy was used as additional extra driving force for acceleration of thermally activated processes of chemical ordering of FePt film and decrease of phase transformation temperature (by 100оС) of chemically disordered magnetic-soft А1(FePt)FCC phase to chemically ordered magnetic-hard L10(FePt)FCТ phase with superstructure.
It is based reasonability of use of alloing elements (Ag, Au, Cu) with limited solubility in FePt alloy for effective control parameters and crystalline supperlatice orientation and also limitation of grain growth and position of film easy magnetization axis normal to substrate surface.
It is carried out complex experimental investigations of multilayer nanoscaled film compositions that allows to form L10(FePt)FCТ phase with high coercitivity (Нс ~ 20-30 кОе), saturation magnetization (~ 1500 еmu/cm3), with squared shape of magnetization curve and Mr/Ms ratio close to 1 in surface layers.
It is developed recommendatons for choice of technological parameters of process of formation and stabilization of FePt films the use of ones gives an opportunity to increase recording density and information storage by thermally activated method up ~ 250 Тbіt/сm2 instead of reached at present 60 Gbіt/сm2.

Problem solved:
Decrease necessity of geometry sizes of information medium at increase of their density.

Potential customers, markets:
Japan, Korea, China