Figure 6
From: Thin film epitaxial [111] Co\(_{50}\)Pt\(_{50}\): structure, magnetisation, and spin polarisation
Magnetisation characterisation of Al\(_2\)O\(_3\)(sub)/Pt (4 nm)/CoPt(\(d_\text {CoPt}\))/Pt (4 nm) sheet films with the applied field oriented out-of-plane (\(\blacktriangle \)) and in-plane (\(\blacktriangleright \)). (a,b) Magnetic hysteresis loops acquired at a temperature of 300 K for \(d_\text {CoPt}=4\) nm. The sample growth temperature is (a) \({350}\,^\circ \hbox {C}\), corresponding to \(L1_1\) crystal structure, (b) \({800}\,^\circ \hbox {C}\), corresponding to \(L1_0\) crystal structure. The diamagnetic contribution from the substrate has been subtracted. (c,d) Magnetic moment per area versus \(d_\text {CoPt}\) for growth temperature of (c) \({350}\,^\circ \hbox {C}\) (with zoomed region inset) and (d) \({800}\,^\circ \hbox {C}\). The significant contribution to the uncertainty in moment/area is from the area measurements of the sample portions. The magnetisation and uncertainty therein is determined from the fit to Eq. (1) (solid lines) and gives a best fit of \(M=750\pm 50\) emu/cm\(^3\) and \(M=520\pm 50\) emu/cm\(^3\) for the \(L1_1\) and \(L1_0\) crystal structures respectively. (e,f) The squareness ratio (\(M_s/M_r\)) versus \(d_\text {CoPt}\) for growth temperature of (e) \({350}\,^\circ \hbox {C}\) and (f) \({800}\,^\circ \hbox {C}\).
