Pressure study of the magnetic and electrical properties of the Eu-Yb alloy system
PhysRevB_32_7483.pdf 1.71 MB
Measurements of the ac magnetic susceptibility, magnetization, and electrical resistivity at hydrostatic pressures up to 15 kbar and of the thermal expansion were made for the EuxYb1-x alloy system (x≤0.4) in temperatures from 1.6 to 400 K. The paramagnetic-ferromagnetic transition temperature Tc versus pressure p curve for x=0.025 has a maximum near p=1 kbar. For x=0.25, Tc decreases and the ferromagnetic–spin-glass-like transition temperature Tt increases at rates of ΔTc/Δp=-9.5 K/kbar and ΔTt/Δp=+1.7 K/kbar, respectively. The ferromagnetic region disappears near p=2.5 kbar, and above it the paramagnetic–spin-glass-like transition temperature Tg, which is pressure insensitive, appears. The Tg value for x=0.35 decreases initially and increases slowly with increasing p above p=2 kbar at a rate of ΔTg/Δp=+0.15 K/kbar. Both the magnetization in the ferromagnetic concentration range and the value of the ac magnetic susceptibility near Tg in the spin-glass-like state decrease with increasing p. From electrical-resistivity measurements under various pressures, semiconducting character was observed at the ambient pressure for x=0.35 and the transition from semimetallic to semiconducting states appears with increasing p for x=0.025. Thermal expansion shows the large positive volume magnetostriction. These results of the measurements under pressure are discussed on the basis of the Ruderman-Kittel-Kasuya-Yosida interaction by considering that the dominant variable is the number of carriers (electrons or holes) which is strongly controlled by the pressure.
Physical Review B
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American Physical Society
Copyright (c) 1985 The American Physical Society.
Graduate School of Education
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