Structural and magnetic properties of CoPt(111) films obtained by using solid-phase reactions

The original Co(001)/Pt(111) film structures are obtained by consequent thermal deposition layer with a cubic crystal lattice and Pt(111) from the target, sprayed using a magnetron sputtering technique on a single crystal substrate of MgO(001) in a vacuum of 10 -6 Torr. In the experiments,samples1Сo:3Pt and1Сo:1Pt atomicratio of the totalthickness of about 300 nm are used.Initial samples were annealed inthe temperature range fromto250 ºCto850 ºCinincrements of 50 for 40 minutes. X-ray diffraction analysis showed that in two-layer structures with the atomic ratio of reagents 1/3, at temperatures of annealing at T = 500 and 850 ºС in the interlayer chemical interaction to form phase epitaxial cubic compounds CoPt 3 (L1 2 ) c FCC-lattice (a = 3.856 Å). Annealingof thesesamestructures with 1/1lead to the formation of the second phaseCoPt(L1 0 )withtetragonal distortion, which helps to ensure ahigh value ofthe uniaxialmagnetocrystallineanisotropyconstantK 1 anddetermineseasymagnetization direction(axisc).Synthesizedsample consisting oftwomagnetic phases isthe saturation magnetization, comparable with the value ofM S for the filmL1 2 -CoPt 3 ,planaranisotropywithK 1 = 5.6 ·10 5 erg / sm3andH c ~10 3 E.Newly formedL1 0 -CoPtphasegrowsepitaxiallyon the basis ofpre-synthesized L1 2 -CoPt 3 phasewith the sameorientation relationship. The newly formedL1 0 -CoPtphasegrowsepitaxiallyon the basis ofpre-synthesized L1 2 -CoPt 3 phasewith the sameorientation relationship. Featuresfilms withatomic ratio of Co / Pt = 1/1 at T = 850 ºCis the presence of“rotational” anisotropy due to the exchange interactionof twoordered phases formedCoPt (111) and CoPt 3 (111) with a ferromagneticorder andan easy axis, which can beapplied a magneticfieldto refocus. By changing the ratio of the reactantsin the system, it is possible tochange the sequence ofphase formation.