Mechanical and magnetic properties of Mn-Pt compounds and nanocomposites
| Authors | |
|---|---|
| Year of publication | 2012 |
| Type | Article in Periodical |
| Magazine / Source | Physical Review B |
| MU Faculty or unit | |
| Citation | |
| Web | http://link.aps.org/doi/10.1103/PhysRevB.85.214438 |
| Doi | http://dx.doi.org/10.1103/PhysRevB.85.214438 |
| Field | Solid matter physics and magnetism |
| Keywords | SHORT-RANGE ORDER; MANGANESE; ALLOYS; 1ST-PRINCIPLES; STRENGTH; SURFACE; MNPT3; RAMAN; GAS; CR |
| Attached files | |
| Description | An analysis of mechanical andmagnetic properties of Mn-Pt compounds and nanocomposites is provided using ab initio electronic structure calculations. Adding manganese to platinum matrix reduces the bulk modulus and enhances the Young moduli E-100 and E-111 and shear moduli (c(11) - c(12))/2 and c(44). With increasing Mn content, the theoretical tensile and compressive strengths are also enhanced. On the whole, manganese addition makes the Mn-Pt compounds softer but increases their resistance to shape deformation. Many of these compounds may be considered natural linear nanocomposites. We studied the magnetic configurations of recently found MnPt7 ordered structure and predict an antiferromagnetic state with spins altering along the [100] direction to be the ground state of this compound. Our calculation further predicts antiferromagnetic ordering of MnPt7 below 265 K and confirms the experimental findings that Mn atoms in a Pt matrix preferentially occupy corners and centers of faces of the 2 x 2 x 2 Pt supercell. We further propose structures of Mn-Pt nanocomposites exhibiting the composition of MnPt15 and identify a structure with an antiferromagnetic ordering with spins altering along the [100] direction as the ground state of the MnPt15 nanocomposite. We conclude that structures with lower manganese concentrations exhibit mostly antiferromagnetic ordering, while additional Mn atoms exceeding the atomic concentration of MnPt7 (12.5 at%) build up locally atomic configurations of the MnPt3 type with predominantly ferromagnetic interactions. |
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