Origin of the high-field Hc2 anomaly

Determine the microscopic origin of the additional high-field magnetization anomaly denoted Hc2 in EuMnSb₂ for magnetic fields applied parallel to the c axis, and establish whether it is related to the flop-like transition predicted by the mean-field model for fields applied parallel to the a axis.

Background

Pulsed-field magnetization measurements identified an additional anomaly, Hc2, several tesla below the Eu-spin saturation field for H parallel to c. The mean-field model does not reproduce this anomaly for H parallel to c, although it predicts an Hc2-like spin-alignment feature for H parallel to a. Consequently, the relationship between the observed c-axis anomaly and the model’s predicted a-axis transition remains unresolved.

References

Several questions therefore remain open: (1) Why does such a large magnetic domain imbalance occur, as evidenced from the non-zero off-diagonal elements of $P_{ij}$ for the Bragg peaks (210) and (220)? (2) What is the origin of the signal denoted $H_{\textrm{c}2}$ observed in the high-field magnetization for $H\parallel c$? Is it related to the flop-like transition predicted by the model for $H \parallel a$?

— Resolving the Magnetic Ground State and Field-Induced Transitions in Magnetic Dirac Semimetal Candidate EuMnSb$_2$  (2608.16724 - Chiu et al., 17 Aug 2026) in Section 6, Conclusion and Outlook