Structural and magnetic properties of η-phase manganese nitride films grown by molecular-beam epitaxy

Abstract

Face-centered tetragonal (fct) η-phase manganese nitride films have been grown on magnesium oxide (001) substrates by molecular-beam epitaxy. For growth conditions described here, reflection high energy electron diffraction and neutron scattering show primarily two types of domains rotated by 90° to each other with their c axes in the surface plane. Scanning tunneling microscopy images reveal surface domains consisting of row structures which correspond directly to the bulk domains. Neutron diffraction data confirm that the Mn moments are aligned in a layered antiferromagnetic structure. The data are consistent with the fct model of G. Kreiner and H. Jacobs for bulk Mn3N2 [J. Alloys Compd. 183, 345 (1992)].

Atomic-scale structure of η-phase Mn3N2(010) studied by scanning tunneling microscopy and first-principles theory

“…8 The RHEED pattern of the Mn 3 N 2 film is streaky, indicating epitaxial growth. 7,8 Following growth, the samples are investigated with in situ STM. For normal STM studies, we use electrochemically etched tungsten tips which are cleaned in the ultra high vacuum chamber using electron bombardment.…”

“…The rows in the STM image cross over step edges without interruption or shift, indicating that the surface structure is directly correlated with the bulk structure. 7 We see that there are two domains labeled by η-D1 and η-D2, respectively. Since the substrate [MgO(001)] has 4-fold symmetry, we expect equal quantities of both types of domains, and numerous domain boundaries (DBs) are commonly observed, as indicated by 'DB' in Fig.…”

“…The control of the phases, and therefore the magnetic properties and orientations of manganese nitride grown on MgO(001) using molecular beam epitaxy (MBE), was reported by Yang et al recently. 7,8 The epitaxially grown phases can be controlled by the ratio of manganese to nitrogen and the substrate temperature. We have also recently investigated the surface magnetic structure of η-Mn 3 N 2 (010) using atomic-scale spin-polarized scanning tunneling microscopy (SP-STM).…”

“…[1][2][3][4][5][6][7][8][9][10] Manganese nitride (Mn-N) is interesting due to its magnetic properties. It is known from previous bulk studies that manganese nitride has different bulk phases, including θ (MnN), η (Mn 3 N 2 ), ε (Mn 4 N), and ζ (Mn 5 N 2 , Mn 2 N, and Mn 2 N 0.86 ).…”

Neutron scattering studies of nanomagnetism and artificially structured materials

“…While much research has been dedicated to the analysis of bulk antiferromagnets, wide-angle neutron diffraction has recently been used to characterize antiferromagnetic films with thicknesses on the order of 30-500 nm. [30,31,32] Microscopy (optical, electron and X-ray) techniques typically resolve local realspace variations in magnetic structure and complement capabilities of statistical probes such as, neutron (and other) scattering techniques, which measure an ensemble average of magnetic structure. Magnetic microscopy techniques such as magnetic force and scanning electron with polarization analysis microscopies have excellent sensitivity to magnetic domain structure.…”