61219-26-9Relevant articles and documents
Growth and magnetic properties of epitaxial MnAs thin films grown on InP(001)
Yokoyama,Ohya,Tanaka
, (2006)
Epitaxial ferromagnetic MnAs thin films have been grown by molecular-beam epitaxy on semi-insulating InP(001) substrates. The MnAs c axis (MnAs[0001]) lies along the InP[110] axis, and the easy magnetization axis is in-plane, along the MnAs[1120] axis, which is parallel to the InP[110] axis. The ferromagnetic transition temperature of the MnAs films on InP(001) was estimated to be 321 K. The structural and magnetic properties of MnAs thin films grown on InP(001) substrates are similar to those of type-A MnAs films grown on GaAs(001) substrates. The feasibility of growing monocrystalline ferromagnetic layers on InP(001) will open up the possibility of monolithic integration of magnetic functions with InP-based optoelectronics devices.
Growth and characterization of ferromagnetic MnAs films on different semiconductor substrates
Bolzan,Bergenti,Rossetto,Zanella,Dediu,Natali
, p. 221 - 224 (2007)
MnAs thin films were grown by metalorganic vapour-phase epitaxy (MOVPE) on GaAs(0 0 1), Si(0 0 1) and oxidised silicon substrates. All films are crystalline and contain only the ferromagnetic α-MnAs phase. X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements show that films on GaAs(0 0 1) have strong preferential orientation, developing elongated grains parallel to [1 -1 0] GaAs while films on bare and oxidised Si are polycrystalline with irregular-shaped, randomly oriented grains. Magneto-optic Kerr effect (MOKE) measurements show good magnetic properties for films on GaAs, such as strong in-plane anisotropy and squareness of the hysteresis loop in the easy direction. A Curie temperature of 340 K, remarkably higher than the bulk material (315 K), was found for a 65 nm thick film on GaAs. Films grown on bare and oxidised silicon wafers had lower Curie temperature and were magnetically isotropic.
State diagram of the Zn3As2-MnAs system
Marenkin,Fedorchenko,Trukhan,Trukhanov,Shoukavaya,Vasil'Ev,Zhaludkevich
, p. 1578 - 1582 (2015)
The Zn3As2-MnAs system was studied by X-ray powder diffraction, differential thermal, and microstructural analyses. This system is of the eutectic type with the eutectic coordinates (30 wt % (50 mol %) Zn3As2, 70 wt % (50 mol %) MnAs, T melt = 815°C). The MnAs solubility boundary on the side of Zn3As2 is 10 wt %. Zn3As2 alloys containing more than 10 wt % MnAs are ferromagnetic with T c ~ 320 K. Their magnetization increases with increasing MnAs content.
Synthesis of Ferromagnetic Alloys Semiconductor–Ferromagnet in the CdAs2–MnAs System
Fedorchenko, I. V.,Kozlov, V. V.,Marenkin, S. F.,Ril’, A. I.
, p. 1219 - 1225 (2020)
Abstract: Semiconductor–ferromagnet alloys in the CdAs2–MnAs system were synthesized in evacuated ampules. Differential thermal analysis (DTA), X-ray powder diffraction analysis, differential scanning calorimetry, and scanning electron microscopy showed that this system is eutectic (of the acicular type), and the coordinates of the eutectic are (6 ± 0.5 mol % MnAs, Tmelt = 614 ± 1°C). The liquidus lines constructed based on the thermal events of melting in DTA are 40–50°C higher than the lines constructed based on the thermal events of crystallization, which is due to the tendency of CdAs2 toward glass transition. The synthesized alloys are ferromagnetic with TC = 315 K, and the magnetization of them increases with increasing MnAs content. The alloys with nanoinclusions ≤40 nm of the ferromagnetic phase MnAs were produced by crystallization from melts at high cooling rates (≤100 deg/s). They have a higher Curie temperature of TC = 353 K and a negative magnetoresistance of ΔR = 2% at 300 K in a saturation magnetic field of 4500 Oe, which is of practical interest for creating magnetic granular spintronic structures.
First-order phase transition at the curie temperature in MnAs and MnAs 0.9Sb0.1
Ishikawa, Fumihiro,Koyama, Keiichi,Watanabe, Kazuo,Asano, Tetsuya,Wada, Hirofumi
, (2006)
Structural transformations of MnAs and MnAs0.9Sb0.1 were investigated by X-ray diffraction in high magnetic fields up to 5 T. The temperature dependence of the magnetization was measured in a magnetic field of 0.01 T and the Curie temperature TC was determined to be 315 K for MnAs and 290 K for MnAs0.9Sb0.1 during heating process. For both compounds, a metamagnetic transition from a paramagnetic to a ferromagnetic state was observed above TC. The X-ray diffraction profile at 319 K for MnAs showed a single phase of an orthorhombic MnP-type structure in zero field. An applied magnetic field of 3 T induced the appearance of a hexagonal NiAs-type structure. On further increase of the magnetic field, a single phase with a hexagonal structure was realized above 3.5 T in a forced-ferromagnetic state. The X-ray diffraction profile at 295 K for MnAs 0.9Sb0.1 showed a hexagonal NiAs-type structure. The coexistence of ferromagnetic and paramagnetic states with different lattice parameters was confirmed in a magnetic field of 2.5 T. The volume expansion induced by a magnetic field was found to be 2.1% for MnAs and 1.1% for MnAs 0.9Sb0.1. 2006 The Physical Society of Japan.
Formation of nanoscale ferromagnetic MnAs crystallites in low-temperature grown GaAs
Wellmann,Garcia,Feng,Petroff
, p. 2532 - 2534 (1997)
We report the formation of nanosize ferromagnetic MnAs crystallites imbedded in low-temperature grown GaAs using Mn+ ion implantation and subsequent annealing. The structural and magnetic properties of the crystallites have been characterized b
Magnetic out-of-plane component in MnAs/GaAs(001)
Ney,Hesjedal,Pampuch,Mohanty,Das,Daeweritz,Koch,Ploog
, p. 2850 - 2852 (2003)
The magnetic out-of-plane component in MnAs/GaAs film was discussed. Its temperature dependence was substantially different from the dominating in-plane magnetization. The analysis showed that the out-of-plane component was due to small isolated magnetic
NUCLEAR MAGNETIC RESONANCE OF 55Mn AND 75As IN MnAs.
Pinjare,Rao
, p. 27 - 32 (1982)
Four sets of NMR signals, two each, from **5**5Mn and **7**5As nuclei have been observed. The temperature dependences of **5**5Mn resonances have been studied from 77 to 311 K and that of **7**5As, from 77 K to about 250 K. The results show that there is a phase transition at T//1 approximately equals 220 K. This transition may be due to introduction of a local spontaneous distortion in the region of the domain walls in the lattice, resulting in lowering of symmetry at low temperatures. Another possibility is the canting of spins which would lower the magnetic group symmetry.
Schottky barrier height of ferromagnet/Si(001) junctions
Sugiura, Kuniaki,Nakane, Ryosho,Sugahara, Satoshi,Tanaka, Masaaki
, (2006)
The Schottky barrier height of ferromagnetic metal/semiconductor junctions is one of the most important parameters for the performance of semiconductor-based spin-electronic devices. The authors investigated the Schottky barrier height φB of ferromagnet/Si(001) junctions with various ferromagnetic metals (CoFe, CoFeB, and MnAs), and found that φB of epitaxial MnAs/Si(001) junctions fabricated by molecular beam epitaxy was 0.16 eV for electrons, which is much lower than φB (～0.7 eV) of CoFe/Si(001) and CoFeB/Si(001) junctions. This implies that MnAs is a promising ferromagnetic material for Si-based spin-electronic devices, especially for the source and drain of spin metal-oxide-semiconductor field effect transistors.
Carbon-doping effects on the metamagnetic transition and magnetocaloric effect in MnAsCx
Cui,Liu,Zhang,Li,Liu,Yang,Zhao,Zhang
, p. 2223 - 2226 (2010)
Carbon doping effects in MnAs alloys have been investigated. More carbon doping in MnAs alloys leads to lower Curie temperature, larger thermal hysteresis and sharper slope of the dependence of critical field on reduced temperature due to severe lattice distortion. The obtained maximum of magnetic entropy change for a field change of 5 T is about 12.8 J kg-1 K-1 near room temperature, and increases with more doping carbon content to about 22.4 J kg-1 K-1 in MnAsC0.03 and 13.2 J kg-1K-1 in MnAsC0.05.
