Effects of Mn doping on temperature-dependent magnetic properties of L1 FeMnPt

Abstract

We report the effect of Mn doping on temperature-dependent magnetic properties of L10 FeMnPt (001) epitaxial films. (001) textured L10 Fe50−xMnxPt50 (x = 0, 5, 10, 15, 20 at. %) films were prepared by cosputtering Fe, Pt, and Mn onto MgO single crystal substrates at 550 °C. θ–2θ XRD scans indicated the lattice parameter c increased whereas the ordering parameter S decreased with Mn doping. The thermal magnetic properties measured using a superconducting quantum interference device showed that Curie temperature TC could be reduced to 500 K with 15 at. % Mn doping, but Ku was decreased to 1.6 × 107 erg/cm3. The relation of temperature-dependent anisotropy and saturation magnetization showed that it did not obey the Callen–Callen theory.

Effect of Mn addition on the thermal stability and magnetic properties of rapidly-quenched L10 FePt alloys

“…However, for the degree of ordering, contradictory results were found: while some reports indicate an increase of the ordering degree with the addition of Mn [12,15], some others report the opposite [17,18]. Also, magnetic properties such as the saturation magnetization M s [14,15,19,20] and the magnetocrystalline anisotropy MCA [12,15,18e20] have different evolution with Mn content according to different investigators.…”

“…While MnPt also forms a L1 0 phase which is antiferromagnetic, the gradual replacement of Fe with Mn leads to a gradual decrease of the c/a ratio. The addition of Mn triggers the formation of a ternary FeMnPt L1 0 phase with reduced Curie temperature [12]. Nevertheless, this is also accompanied by a decrease in the magnetocrystalline anisotropy.…”

Effect of doping concentration on absorbance, structural, and magnetic properties of cobalt-doped ZnO nano-crystallites

“…Although these peaks are very feeble, they exist and represent agglomeration of cobalt atoms at higher doping ratios. Distortion or other type of degradation (like shift of peaks and decrease of crystallinity) was not observed in doped samples as claimed by researchers working with Fe and Mn as dopants [11,12]. The crystallite size calculated using Scherer's formula was found to be 14.61, 14.9, and 15.27nm for 1%, 3%, and5% (impurity vs. crystallite size graphically shown in Figure 2) cobalt-doped ZnO, respectively.…”

In-plane/out-of-plane disorder influence on the magnetic anisotropy of Fe1−yMnyPt-L1 bulk alloy

“…However, in the manufacturing process, the media must be annealed to transform a face-centered cubic (fcc) A1 initial phase into an L1 0 highly chemically ordered alloy. As was pointed out in some recent experimental and theoretical works, [7][8][9][10][11][12] introducing into the FePt-L1 0 alloy magnetic or non-magnetic species such as Ni, Mn, or Cu, respectively, permits the reduction of T C and control of the MAE values as the Fe concentration decreases.…”

“…However, experimental studies 8,9,11,12,14 achieve variations in n eff using substitution of Fe sites with impurity atoms such as Ni, Mn, Co, Cr, or Cu. Recently, 7 we showed that the alloying process itself produces variations in atomic structure and consequent changes in band structure which strongly affect the MAE and saturation magnetization leading to important differences with the fixed band structure approach.…”