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Samples with inversion parameter values (δ) ranging from 0.27 to 0.14 while maintaining the crystallite size value have been successfully fabricated from commercially available powders by mechanical grinding and thermal annealing treatments at temperatures ranging between 400 and 600 °C. Detailed characterization studies of these samples using X-ray, neutron diffraction and magnetic measurements have confirmed for the first time the simultaneous coexistence at 2 K of short range antiferromagnetic and ferrimagnetic ordering for a wide range of the inversion parameter. The magnetic phase diagram obtained is different from the one previously reported, which shows at 2 K the coexistence of long range antiferromagnetic order and short range order for values of inversion parameters less than 0.1 and the presence of a ferrimagnetic order only for values of δ > 0.2. At room temperature, the Rietveld analysis of NPD patterns and the magnetization curves showed a paramagnetic behavior in the samples with δ ≤ 0.1. For the samples with higher cationic inversion, typical hysteresis curves of ferrimagnetic materials were observed and the saturation magnetization values obtained agree quite well with the net magnetic moment obtained from the Rietveld refinement of the neutron diffraction patterns. [ABSTRACT FROM AUTHOR]

We report on structural and magnetic properties of a SmCuAl 3 single crystal. The sample quality, phase and structure purity were investigated by means of x-ray and neutron diffraction, BSE electron microscopy and EDX analysis. The crystal structure was identified to be of a tetragonal BaNiSn 3 -type (space group I4mm , 107). Magnetization measurements revealed two magnetic phase transitions: from paramagnetic to ferromagnetic state at T c = 28 K and another transition at T N = 6.6 K connected with a development of the antiferromagnetic component of magnetic moments. Both ferromagnetic and antiferromagnetic components are followed down to lowest temperature. Possible origins of the phase transition at 28 K are discussed. Paramagnetic data are well described assuming a Sm3+ ground-state-multiplet splitting in crystalline environment. Crystal field parameters are estimated and used for magnetization and specific heat calculations revealing a qualitatively good agreement with the experimental data. • SmCuAl3 single crystal was prepared. • Magnetization and specific heat data are well described by crystal field model. • Both ferromagnetic and antiferromagnet ordering were observed. • Obtained results are well consistent with other RCuAl3 compounds (R = rare-earth). [ABSTRACT FROM AUTHOR]