Enhanced Magnetic Ordering in Sm Metal under Extreme Pressure

The dependence of the magnetic ordering temperature T_o of Sm metal was determined through four-point electrical resistivity measurements to pressures as high as 127 GPa. A strong increase in T_o with pressure was observed above 40 GPa. In this pressure range Sm ions alloyed in dilute concentration with superconducting Y exhibit giant Kondo pair breaking. Both results suggest that for pressures above 40 GPa Sm enters a highly correlated electron state, likely related to a Kondo lattice, with an unusually high value of T_o. Similar results were found previously for Nd [1], Tb [2], and Dy [3] and their dilute magnetic alloys with superconducting Y. Both Y(Sm) and Y(Nd) alloys display record-high pair breaking ΔT_c as large as 40 K/at.%.
[1] J. Song, W. Bi, D. Haskel and J. S. Schilling, Phys. Rev. B 95, 205138 (2017)
[2] J. Lim, G. Fabbris, D. Haskel, and J. S. Schilling, Phys. Rev. B 91, 174428 (2015).
[3] J. Lim, G. Fabbris, D. Haskel, and J. S. Schilling, Phys. Rev. B 91, 045116 (2015).