Fabrication of L1-MnAl perpendicularly magnetized thin films for perpendicular magnetic tunnel junctions

Abstract

Structural and magnetic properties of MnAl thin films with different composition, growth temperature, and post-annealing temperature were investigated. The optimum condition for fabrication of L10-MnAl perpendicularly magnetized thin film deposited on Cr-buffered MgO single crystal substrate was revealed. The results of x ray diffraction indicated that the MnAl films annealed at proper temperature had a (001)-orientation and L10-ordered structure. The L10-ordered films were perpendicularly magnetized and had a large perpendicular anisotropy. In addition, low surface roughness was achieved. For the optimized fabrication condition, the saturation magnetization Ms of 600 emu/cm3 and perpendicular magnetic anisotropy Ku of 1.0 × 107 erg/cm3 was obtained using the Mn48Al52 target at deposition temperature of 200 °C and post-annealing temperature of 450 °C.

Epitaxial Growth of Hard Ferrimagnetic Mn3Ge Film on Rhodium Buffer Layer

“…Figure 1e shows typical K u and M s data from our work and from other groups for c-axis-oriented epitaxial films of several Mn-based alloys and the values for conventional hard magnetic materials [14]. The L1 0 phase of the Mn-Al binary system is metastable, but epitaxial films were reported recently ([a], [b] in Figure 1e) [15,16]. The L1 0 phase of the Mn-Ga binary system is thermodynamically stable at room temperature (RT), and high-quality films have been grown on several types of buffer layers using various techniques ([c], [d] in Figure 1e) [17,18] Figure 1e) [17,19,20].…”

“…[a]: [15] Mn-based hard magnets are very good candidates for magnetic random access memory (MRAM) applications [24,25] because some of them show a small saturation magnetization as well as a large uniaxial magnetic anisotropy. The Gilbert magnetic damping is expected to be smaller than that of hard magnets containing heavy elements because the addition of heavy elements or rare-earth elements to magnetic materials tends to increase the Gilbert damping [25].…”

High perpendicular magnetic anisotropy in D22-Mn3+xGe tetragonal Heusler alloy films

“…Mn-based alloys such as Mn-Ga, [7][8][9][10][11][12][13][14][15] Mn-Co-Ga, 16,17 Mn-Al, 18,19 and Mn-Al-Ge, 20 which possess tetragonal crystal structures have been studied as candidates for STT-MRAM and exhibited low M s , low a, and high K u . Of these alloys, the Mn-Ga system has been studied the most intensively, exhibiting M s % 200-600 emu/cm 3 , 10 a % 0.008-0.015, 10 K u % 10-23.5 Merg/cm 3 , 8,10 and P % 40-58%.…”

Controllable perpendicular hysteresis steps in highly perpendicular magnetic anisotropic CoPt/AlN layered structures

“…1 Perpendicular MTJ (pMTJ), whose magnetization is along the direction of film normal, is of great interest as it has a potential for realizing next-generation high-density non-volatile memory and logic chips with high thermal stability and low critical current for current-induced magnetization switching. 2 The conventional approaches to achieve perpendicular magnetic anisotropy in pMTJ includes anisotropic growth of the ferromagnetic layers along their "easy" magnetization directions, [3][4][5] perpendicularly pinning of the ferromagnetic layer by using a coupling layer, 6,7 and manipulation of magnetization of metallic multilayer. 8,9 In these cases, anti-parallel configuration of perpendicular magnetization is essential for pMTJ effect, which originates from different coercivities of the ferromagnetic layers.…”