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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Evolution of Fe magnetic order in NdFexGa ₁- xO₃
M Parra-Borderías1, F Bartolomé, J A Rodríguez Velamazán
1Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, Universidad de Zaragoza-CSIC, Pedro Cerbuna 12, 50009 Zaragoza, Spain.
Abstract:
The evolution of the crystal structure and magnetic properties with Fe content in NdFe(x)Ga(1 - x)O(3) has been studied by magnetization, ac-susceptibility, x-ray and neutron scattering techniques for x ≥ 0.2 in order to determine the phase diagram of the series. X-ray diffraction shows that the crystallographic structure of NdFe(x)Ga(1 - x)O(3) can be described in the space group Pbnm for all x values. Both the magnetic ordering and spin reorientation temperatures of the Fe magnetic sublattice decrease with iron concentration due to the presence of magnetic vacancies occupied by Ga. The long-range Fe magnetic ordering disappears for x ≤ 0.3, while ac-susceptibility measurements evidence the presence of short-range Fe ordered clusters and superspin-glass-like effects for x well below the percolation threshold. The magnetic structure of the compounds, including the spin reorientation temperature range, is determined by high-resolution neutron diffraction analysis. Although the presence of finite magnetic clusters for x values close to percolation is evidenced, the study of a percolation quantum phase transition in this series is hindered by the presence of Nd magnetic moments and a sizeable distribution of composition Δx around the nominal value.
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