Investigation in the Ga-rich side of the Mn–Ga system: Synthesis and crystal structure of MnGa4 and MnGa5−x (x ∼ 0.15)

Antiferromagnetic ground state in theMnGa4intermetallic compound

“…On the other hand, the observed increase of χ(T ) above 100 K is incompatible with the putative Pauli paramagnetism. Indeed, measurements above room temperature reveal an antiferromagnetic transition at T N = 393 K. Above T N , χ(T ) decreases with increasing temperature, but does not follow the Curie-Weiss law up to at least 650 K, whereas at 670 K the decomposition of MnGa 4 occurs according to the reported phase diagram [14]. Thus, magnetic susceptibility measurements suggest that MnGa 4 is antiferromagnetically ordered with the sizable Neel temperature of 393 K. The high value of T N apparently concealed the antiferromagnetic nature of MnGa 4 in the previous study, where only measurements up to 300 K were reported [12].…”

“…The bulk polycrystalline sample of MnGa 4 for neutron powder diffraction was prepared by annealling the stoichiometric mixture of Mn and Ga in an evacuated quartz ampule. The synthetic conditions were chosen on the basis of the reported phase diagram [14]. The ampule was heated in a programmable furnace to 900 • C, annealed at this temperature for 4 days to ensure homogeneity of the mixture, cooled at the rate of 20 • C/h to 380 • C, and annealed at 380 • C for 10 days.…”

Structure and magnetism in Ga-rich MnGa/GaN thin films and unexpected giant perpendicular anisotropy in the ultra-thin film limit

“…Lattice parameters (a and c) and interplanar distances (d hkl ) for the observed phases and orientations are indicated in Table 2; we also report the lattice parameters for bulk samples. [3,22,23,26] The three main phases observed in XRD are known to be tetragonal [3,17,22], although the peak at ≈ 46 • could also be identified as corresponding to the cubic MnGa 4 crystal. However, based on RBS and AES values (discussed below) it is more probable that this peak corresponds to Mn 2 Ga 5 for our samples.…”

“…[19] Despite the extensive literature on Mn-rich and stoichiometric MnGa alloys, the Ga-rich regime has received far less attention. [6,[20][21][22][23] In particular, the growth, structure, and magnetism of Ga-rich MnGa when deposited onto wide-gap GaN are still not addressed.…”

New Tetragonal ReGa5(M) (M = Sn, Pb, Bi) Single Crystals Grown from Delicate Electrons Changing

“…This can be observed in the superconductors Mo 8 Ga 41 and Mo 6 Ga 31 -as the electron counts decrease, the T c increases and the clusters form vertex-sharing interactions rather than edge-sharing [9]. MnGa 4.96 is another Ga-rich cluster which crystallizes into a tetragonal unit cell with capped face sharing Mn@Ga 8 clusters and correspondingly exhibits no superconductivity [10]. Therefore, the stoichiometry and valence electrons from the transition metal of endohedral gallide clusters play a critical role in the exo-bond formations, i.e., electron-rich clusters prefer edge-sharing while electron-poor ones prefer vertex-sharing clusters, which as a result, directly affects the T c .…”