2018年度 第2回 :Quantum tricritical points, quantum wing critical points and more in the phase diagram of metallic quantum ferromagnets
Studies of the temperature-pressure (T-p) phase diagram of metallic quantum ferromagnets have revealed that ferromagnetic quantum criticality is avoided in two ways : either the transition becomes of the first-order at a tricritical point before being suppressed such as in UGe2 [2,3], or a transition to modulated magnetic phases appear such as in LaCrGe3 . We have shown that the addition of a magnetic field (H) can restore quantum criticality at the end of “wings” in the T-p-H phase diagram in both UGe2 and LaCrGe3 . Our careful study of the “wings” near the tricritical point reveal new rules that apply to the T-p-H phase diagram . We discuss our experimental T-p-H phase diagrams of UGe2, LaCrGe3, and CeTiGe3 and how these compounds illustrate different strength of quantum fluctuations based on recent theoretical results .
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