40 T Soft X-ray Spectroscopies on Magnetic-Field-Induced Valence Transition in Eu(Rh_1−xIr_x)₂Si₂ (x = 0.3)

Fermi surface of a system with strong valence fluctuations: Evidence for a noninteger count of valence electrons in EuIr2Si2

“…A magnetic field shall always stabilize the Eu 2+ 4 f 7 state, because of its huge magnetic moment of 7μ B . Indeed, in valence-fluctuating Eu systems located in the regime where one observes a temperature-induced first-order valence transition, such as in Eu(Rh 1−x Ir x ) 2 Si 2 in the range 0.2 < x < 0.6, application of a magnetic field at low temperatures also results in a strong first-order transition to a magnetic divalent Eu state, in full analogy with the effect of increasing temperature [29,53]. Reason for this analogy is the large moment (magnetic field) and the large magnetic entropy (temperature) of the 4 f 7 state.…”