Anomalous Magnetic-Field-Hysteresis of Quantum Oscillations in κ-(BETS)2FeBr4

Resistive properties and phase diagram of the organic antiferromagnetic metalκ−(BETS)2FeCl4

“…This enhanced damping of the oscillations in the down-sweep is obviously caused by the same additional, field-dependent scattering that causes the hysteresis of the nonoscillating magnetoresistance presented above. SdH oscillations very similar to those presented here have also been observed in the AFM state of the κ-Br salt [15,27]. The magnetic ordering in κ-Br is more robust: in the field perpendicular to the layers it survives up to 5.5 T, see, e.g.…”

“…A hysteresis in the interlayer magnetoresistance has also been reported for the κ-Br salt [27]. As opposed to our case, in that salt a clear difference between the initial up-sweep and the following down-sweep of the field was observed all the way from H k down to the SC transition at which the resistance dropped to zero.…”

“…3. For the κ-Br salt it was proposed that the hysteresis originates from additional scattering on domain walls, which may appear upon entering the AFM state from the high-field PM state with saturated Fe 3+ spins [27]. On the other hand, our data in Fig.…”

“…We note that the resistance is lower in the down-sweep than in the up-sweep both in κ-Br [27] and in κ-Cl. At first glance, this contradicts the suggested enhancement of scattering in the down-sweeps.…”

Interplay between the d - and π -electron systems in magnetic torque of the layered organic conductor κ -(BETS) 2MnVyaselev1, Biberacher2, Kushch3 et al. 2017Phys. Rev. B7180View full textAdd to dashboardCite

“…For example, a considerable π-d coupling in λ-(BETS) 2 FeCl 4 leads to a metal-insulator transition in the π-electron system triggered by an antiferromagnetic (AF) ordering of localized Fe 3+ spins [7] and to a spectacular phenomenon of superconductivity induced by a strong magnetic field [8,9]. In the κ-(BETS) 2 FeX 4 salts the π-d coupling is weaker; however it can be readily traced in a reconstruction of the Fermi surface caused in the AF state [10][11][12], high-field re-entrant superconductivity [13,14], and protection of the low-field superconductivity by the AF ordering [13,15].In the present compound the π-d interactions seem to be even weaker. While the metalinsulator transition at T MI ≈ 21 K [1] might, at first glance, appear similar to that in λ-(BETS) 2 FeCl 4 , it is most likely driven by purely the Mott-insulating instability of the π-electron system and not by an AF instability of the localized d-electron spins.…”