Magnetic Ordering at Anomalously High Temperatures in Nd and Dy at Extreme Pressures: What about Pr and Yb?

Under sufficiently high pressure one anticipates that the 4f state of a given lanthanide becomes unstable, leading to highly correlated electron effects and exotic physics. Recent four-point resistivity measurements on Nd metal to 2 Mbar pressure reveal that its magnetic ordering temperature T_o soars to anomalously high values, in analogy with earlier results on the lanthanide Dy. In addition, giant superconducting pair-breaking and resistivity minima are observed in the dilute magnetic alloy Y(Nd) revealing the presence of exotic Kondo effect phenomena that may be responsible for the anomalously high values of T_o in Nd metal.
Unlike most lanthanides at ambient pressure, Yb does not order magnetically and Pr orders at temperatures well below 1 K, since divalent Yb is magnetically inert with a completely filled 4f¹⁴ orbital and trivalent Pr has a crystal-field-split singlet ground state. Applying extreme pressure can significantly alter both the electronic and crystal structure of materials and thus possibly induce magnetic ordering in Yb or Pr at temperatures above 1 K.