1. Size, disorder, and charge doping effects in the antiferromagnetic series Eu1-AGa4 (A = Ca, Sr, or La)
- Author
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Emilia Morosan, James C. Fettinger, Chien-Lung Huang, Macy Stavinoha, Susan M. Kauzlarich, and Kasey P. Devlin
- Subjects
Materials science ,Doping ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Inorganic Chemistry ,Tetragonal crystal system ,Magnetization ,Crystallography ,Electrical resistivity and conductivity ,Materials Chemistry ,Ceramics and Composites ,Antiferromagnetism ,Physical and Theoretical Chemistry ,0210 nano-technology ,Anisotropy ,Single crystal ,Monoclinic crystal system - Abstract
EuGa4 hosts a magnetic Eu2+ sublattice surrounded by a network of covalently-bound Ga atoms with the BaAl4 structure type (space group I4/ m m m ). In this study, we present the synthesis and characterization of three new single crystal substitutional series Eu A x 1 − x Ga4 with A = Ca, Sr, or La. X-ray diffraction and resistivity measurements show that Ca substitution induced a structural phase transition from the tetragonal crystal structure at high temperatures to the monoclinic crystal structure (CaGa4 type, space group C2/m) at low temperatures and suppressed the antiferromagnetic ordering temperature to 8.8 K for x = 0.45. Comparatively, La or Sr substitution maintained the tetragonal crystal structure and suppressed the antiferromagnetic ordering temperatures to 6.7 K and 1.6 K for (A, x) = (La, 0.37) and (Sr, 0.91), respectively. In addition to suppressing the magnetic order, magnetization and specific heat measurements indicate the onset of anisotropic metamagnetic transitions in (La, 0.18), (La, 0.37), and (Sr, 0.63), along with an incommensurate-to-commensurate magnetic transition in (Sr, 0.38). By comparing these effects of doping EuGa4, we show how size, disorder, and charge determine the structure-physical property relations in EuGa4.
- Published
- 2020