Chemically ordered MnPt ultrathin films on Pt(001) substrate: Growth, atomic structure, and magnetic properties

Marcio Soares (1) , Maurizio de Santis (1) , Hélio Tolentino (2) , Aline Y. Ramos (3) , Mohammad El Jawad , Yves Gauthier (1) , Fikret Yildiz (4) , Marek Przybylski (4)

1 NEEL - SIN - Surfaces, Interfaces et Nanostructures
2 NEEL - CRG - CRG & Grands instruments
3 NEEL - MRS - Matériaux, Rayonnements, Structure
4 MPI-HALLE - Max-Planck-Institut für Mikrostrukturphysik

Ultrathin MnPt films have been grown on Pt(001) single crystals by alternate deposition of Mn and Pt and studied in situ by grazing incidence x-ray diffraction. The growth mode and chemical order strongly depend on the deposition conditions. At room temperature, a 3D growth mode for Pt leads to a disordered and rough MnPt film. After annealing at 770 K, chemical order develops with the tetragonal axis oriented in the surface plane. At 570 K, Pt grows in a quasi layer-by-layer mode. For all depositions, and even after annealing, Mn remains essentially at the surface with negligible diffusion into bulk. As a consequence, the film deposited at 570 K is chemically ordered, with the tetragonal axis oriented mainly perpendicular to the surface. Coupled to ferromagnetic layers with in-plane (out-of-plane) anisotropy, these ultrathin (≈3 nm) MnPt films exhibit exchange bias properties and enhanced coercivity at low temperature.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Marcio Soares, Maurizio de Santis, Hélio Tolentino, Aline Y. Ramos, Mohammad El Jawad, et al.. Chemically ordered MnPt ultrathin films on Pt(001) substrate: Growth, atomic structure, and magnetic properties. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2012, 85 (20), pp.205417. ⟨10.1103/PhysRevB.85.205417⟩. ⟨hal-00696368⟩