X-ray analysis of the crystal structure and thermal expansion of the intermetallic compound (Tb0.8Gd0.2)3Co crystallized in space

Abstract On board the orbital complex “Salyut-6-Soyuz” during long-term near 0-gravity space flight the experiment on crystallization of the quasibinary intermetallic compound (Tb 0.8 Gd 0.2 ) 3 Co was performed. The experiment included melting of the initial alloy of the stoichiometric composition prepared on Earth, exposure at T > T melt in the absence of temperature gradient and cooling in the microgravity conditions. The flight and the ground-based samples produced under identical time-temperature conditions were investigated by means of the low-temperature X-ray technique and thermomagnetic analysis in the temperature interval 4.2–300 K. The anomalies have been found on the temperature dependences of the lattice parameters of the ground-based and flight samples at the temperatures of the phase magnetic transitions. The magnetic nature of the observed anomalies is evident and confirmed. The analysis of the X-ray diffraction spectra has shown that the perfection of the crystal structure of the flight sample is sufficiently higher compared to that of the ground-based sample from the point of view of the shape, half-widths of the diffraction peaks and better resolution.