(Gd,Tb,Dy,Ho,Er)Mn6Sn6 is a high-entropy kagome metal with a hexagonal HfFe6Ge6-type structure featuring an undistorted Mn kagome net and randomly occupied rare-earth sites.
It exhibits multiple spin reorientation transitions—from in-plane to out-of-plane and canted ferrimagnetic states—driven by competing anisotropies and exchange interactions.
Robust Dirac crossings, strictly linear magnetoresistance, and intrinsic anomalous Hall effects indicate preserved topological kagome electronic features despite configurational disorder.
(Gd,Tb,Dy,Ho,Er)Mn6Sn6 denotes a high-entropy member of the RMn6Sn6 kagome-metal family, realized experimentally as (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn6. It retains the hexagonal HfFe6Ge6-type framework with space group P6/mmm, in which Mn forms an undistorted kagome net and the rare-earth $1a$ site is randomly occupied by five lanthanides. Within the broader RMn6Sn6 series, this structural motif is associated with ferrimagnetism, Dirac crossings, flat bands, and large intrinsic anomalous Hall responses; in the high-entropy variant, the same backbone coexists with multiple spin-reorientation transitions, metamagnetic features, and strictly linear non-saturating magnetoresistance (Liu et al., 30 Jul 2025).
1. Crystal chemistry and high-entropy realization
Single crystals of the high-entropy compound were grown by Sn-flux using elemental Gd (99 %), Tb (99.9 %), Dy (99.8 %), Ho (99.9 %), Er (99.9 %), Mn (99.99 %) and Sn (99.9999 %), with nominal ratio R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:20. The charge was heated to $1100\,^\circ\mathrm{C}$, held for 48 h, cooled from RMn6Sn60 to RMn6Sn61 at RMn6Sn62, and the excess flux was removed at RMn6Sn63. The resulting crystals are plate-like, with typical size RMn6Sn64 (Liu et al., 30 Jul 2025).
Single-crystal X-ray diffraction shows that the structure is the same RMn6Sn65 phase as in the parent RMn6Sn66 compounds. The RMn6Sn67 site at RMn6Sn68, RMn6Sn69, is randomly occupied by (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn60; Mn occupies (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn61 at (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn62 with occupancy (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn63; and Sn occupies (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn64 and (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn65 positions. At 123 K the refined lattice constants are (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn66 Å and (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn67 Å, while at 300 K they are (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn68 Å and (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn69 Å. No symmetry-lowering or volume anomaly is seen between 123 K and 300 K. The selected bond lengths at 300 K are Mn–Mn 60 Å, Mn–Sn 61 Å, and 62–Sn 63 Å, and EDX mapping confirms a homogeneous distribution of all five 64 elements (Liu et al., 30 Jul 2025).
As in the parent Tb, Dy, and Ho compounds, the structural building block along 65 is 66Sn67–Mn–Sn68–Sn69–Sn60–Mn–61Sn62, with 63 atoms at the centers of graphene-like Sn64 hexagons and Mn atoms forming an undistorted kagome net in the 65-plane (Gao et al., 2021). This continuity of the crystallographic scaffold is central to interpreting the high-entropy phase as a disorder-modified member of the same kagome-metal series rather than as a distinct structural class.
2. Magnetic phase sequence and anisotropy competition
Magnetization measurements in 66 T show that the high-entropy compound is paramagnetic above 450 K. A sharp increase in 67 at 68 K marks the onset of in-plane ferrimagnetic order, denoted FIM-69. On cooling below P6/mmm0 K, the easy axis reorients from P6/mmm1 into P6/mmm2, giving a uniaxial FIM-P6/mmm3 state. A second spin reorientation occurs at P6/mmm4 K, evidenced by ZFC/FC splitting; below this temperature the low-P6/mmm5 state is described as a canted-FIM texture (Liu et al., 30 Jul 2025).
Temperature range
Magnetic regime
P6/mmm6 K
PM
P6/mmm7
FIM-P6/mmm8
P6/mmm9
FIM-$1a$0
$1a$1 K
canted-FIM
Curie–Weiss analysis above 500 K gives
$1a$2
with $1a$3, corresponding to $1a$4, and $1a$5 K. The positive $1a$6 is consistent with dominant ferromagnetic Mn–Mn coupling. Arrott plots of $1a$7 versus $1a$8 at $1a$9 K yield straight lines through the origin, indicating a second-order transition at RMn6Sn60 (Liu et al., 30 Jul 2025).
Field-dependent magnetization resolves the anisotropy competition in more detail. At 350 K, RMn6Sn61 is linear, consistent with the paramagnetic state. In the 250–400 K range with RMn6Sn62, rapid saturation by RMn6Sn63 T is consistent with FIM-RMn6Sn64. In the 100–200 K range with RMn6Sn65, the easy axis gradually rotates into RMn6Sn66 under RMn6Sn67 T. For RMn6Sn68–RMn6Sn69 K and field perpendicular to the easy axis, a metamagnetic jump appears at R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:200 T, followed by a slow approach to saturation above 3 T, indicative of field-induced spin reorientation and possible chiral states. Below 50 K, pronounced hysteresis for both field orientations, together with growing remanent moment and coercivity, reflects the low-R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:201 canted-FIM texture (Liu et al., 30 Jul 2025).
3. Exchange hierarchy in the parent series
The microscopic magnetic framework of the series is most fully resolved for TbMnR:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:202SnR:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:203, which is modeled by a minimal local-moment Heisenberg Hamiltonian
R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:204
The intralayer term is a ferromagnetic Mn–Mn exchange within each kagome layer,
R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:205
with R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:206 and R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:207 spin-1 on each Mn. Interlayer couplings comprise Mn–Mn terms R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:208, R:Gd:Tb:Dy:Ho:Er:Mn:Sn=0.2:0.2:0.2:0.2:0.2:6:209, $1100\,^\circ\mathrm{C}$0, and an antiferromagnetic Mn–Tb exchange $1100\,^\circ\mathrm{C}$1, with the Tb moment $1100\,^\circ\mathrm{C}$2. The anisotropy term is
$1100\,^\circ\mathrm{C}$3
with $1100\,^\circ\mathrm{C}$4 and $1100\,^\circ\mathrm{C}$5. Dzyaloshinskii–Moriya terms were found unnecessary to capture the main INS features (Riberolles et al., 2021).
INS establishes a very large Mn kagome magnon bandwidth, with the top of the Mn magnon band approaching $1100\,^\circ\mathrm{C}$6 meV. The low-energy sector contains several distinct scales: a $1100\,^\circ\mathrm{C}$7-point gap $1100\,^\circ\mathrm{C}$8 meV, a bilayer splitting $1100\,^\circ\mathrm{C}$9 meV, and an Mn–Tb ferrimagnetic exchange-field shift RMn6Sn600 meV. A global SpinW fit to RMn6Sn601 data points gives
RMn6Sn602
RMn6Sn603
The dominant intralayer ferromagnetism is therefore accompanied by weaker, competing interlayer Mn–Mn couplings and a substantial antiferromagnetic Mn–Tb interaction (Riberolles et al., 2021).
DFT generalizes this picture across the RMn6Sn604 family. For RMn6Sn605–Lu, RMn6Sn606 is always ferromagnetic and largest, whereas RMn6Sn607 and RMn6Sn608 are weaker and can change sign. RMn6Sn609 scales roughly with RMn6Sn610-4RMn6Sn611 overlap and is largest for Gd, then Tb, Dy, and so on. In TbMnRMn6Sn612SnRMn6Sn613, the ferrimagnetic state is strongly stabilized: using the fitted parameters, the classical energies are RMn6Sn614 meV/f.u. and RMn6Sn615 meV/f.u., so the Mn–Tb coupling overwhelmingly locks the layers into a rigid three-dimensional ferrimagnetic network. More broadly, the weaker RMn6Sn616 and RMn6Sn617 are the same competing interactions that drive helical magnetism in YMnRMn6Sn618SnRMn6Sn619; for RMn6Sn620Gd–Ho, Mn–RMn6Sn621 antiferromagnetic coupling and RMn6Sn622 single-ion anisotropy lock in a collinear ferrimagnet, whereas in ErMnRMn6Sn623SnRMn6Sn624 the Mn–Er coupling becomes so weak that Mn and Er sublattices order separately (Riberolles et al., 2021).
This suggests that the high-entropy compound superposes a robust Mn kagome exchange network, characterized in the parent series by RMn6Sn625 meV and a transferable high-RMn6Sn626 magnon bandwidth RMn6Sn627 meV, with a distribution of RMn6Sn628-dependent anisotropies and Mn–RMn6Sn629 exchange fields. A plausible implication is that the multiple reorientation transitions in RMn6Sn630 are a collective manifestation of this exchange hierarchy under configurational disorder.
4. Magnetotransport and Hall response
The high-entropy compound is metallic throughout the measured range. Its longitudinal resistivity has residual-resistivity ratio
RMn6Sn631
The derivative RMn6Sn632 shows a clear peak at RMn6Sn633 K, in register with a spin-reorientation feature. Magnetoresistance,
RMn6Sn634
remains strictly linear and non-saturating up to the highest fields reported. At 2 K and RMn6Sn635 T, RMn6Sn636. In pulsed fields at 4 K up to 35 T, two distinct linear MR slopes appear, with a kink around 20 T but no saturation even at 35 T. Over 0–20 T, the linear fit is
The ordinary Hall coefficient is RMn6Sn641, indicating an electronlike ordinary Hall channel. Conductivities are obtained from
RMn6Sn642
and the Tian–Ye–Jin scaling
RMn6Sn643
gives RMn6Sn644 in total, or
RMn6Sn645
per Mn kagome layer. The weak dependence of RMn6Sn646 on RMn6Sn647 indicates an intrinsic Berry-curvature origin (Liu et al., 30 Jul 2025).
The parent Tb, Dy, and Ho compounds provide a reference for this interpretation. In those materials, the low-temperature MR for RMn6Sn648 is positive and approximately RMn6Sn649-like below RMn6Sn650 K, while at higher temperature it becomes negative and is attributed to suppression of spin-disorder scattering. Their anomalous Hall response follows
RMn6Sn651
with RMn6Sn652 and RMn6Sn653 for Tb, RMn6Sn654 for Dy, and RMn6Sn655 for Ho, implying negligible skew scattering and dominant intrinsic Karplus–Luttinger physics. The anomalous Hall conductivities at 7 T and 100–300 K are about RMn6Sn656 for TbMnRMn6Sn657SnRMn6Sn658, RMn6Sn659 for DyMnRMn6Sn660SnRMn6Sn661, and RMn6Sn662 for HoMnRMn6Sn663SnRMn6Sn664 (Gao et al., 2021).
5. Kagome electronic structure and topological character
The electronic structure of the parent series is defined by the Mn kagome lattice. High-resolution ARPES and RMn6Sn665 calculations on RMn6Sn666 (RMn6Sn667 Dy, Tb, Gd, Y) show a Dirac-like crossing at RMn6Sn668 located within RMn6Sn669 meV of RMn6Sn670, a Fermi velocity RMn6Sn671, and two weakly dispersive flat bands at approximately RMn6Sn672 eV and RMn6Sn673 eV. Across Gd, Tb, and Dy, the Dirac-cone position, gap, Fermi velocity, and flat-band energies vary by less than 20 meV, indicating that the Mn-derived kagome bands are unusually robust against changes in RMn6Sn674 configuration and magnetic ground state (Gu et al., 2022).
A minimal tight-binding description of these states is the standard nearest- and next-nearest-neighbor kagome model,
RMn6Sn675
In the parent Tb and Ho compounds, first-principles bands show linear crossings at the RMn6Sn676 points, and spin–orbit coupling opens gaps RMn6Sn677 meV for Tb and RMn6Sn678 meV for Ho. The corresponding intrinsic anomalous Hall conductivity is expressed as the Brillouin-zone integral of Berry curvature,
RMn6Sn679
with the sharp Berry-curvature contribution associated with SOC-gapped Dirac crossings near RMn6Sn680 (Gao et al., 2021).
For the high-entropy compound, the reported topological-electronic interpretation is explicitly inherited from this parent-series kagome physics. The relevant features are Dirac crossings at RMn6Sn681, a nearly flat band around RMn6Sn682 eV, and Berry-curvature hot spots generated by partially gapped kagome bands. High-entropy alloying introduces a random RMn6Sn683-site potential that broadens the kagome bands but does not destroy the Dirac-point signatures, as inferred from the robust intrinsic anomalous Hall effect; disorder-induced scattering is argued to suppress extrinsic AHE channels, thereby sharpening the relative role of band-structure Berry curvature (Liu et al., 30 Jul 2025).
A common misconception is that configurational disorder on the rare-earth site should necessarily erase kagome-band topology. The reported behavior does not support that conclusion. Instead, the preserved RMn6Sn684 framework, intrinsic-like Hall scaling, and parent-series ARPES robustness together indicate that the Mn kagome electronic structure remains operative in the high-entropy alloy. This suggests that the topological response is controlled primarily by the Mn-derived band manifold rather than by fine details of any single rare-earth ion.
6. Position within the RMn6Sn685 landscape
Within the parent RMn6Sn686 family, rare-earth substitution is already a magnetic tuning parameter. The series shares a very strong intralayer Mn exchange and dominant ferromagnetic interlayer RMn6Sn687, while weaker RMn6Sn688 and RMn6Sn689 generate magnetic competition. In nonmagnetic-RMn6Sn690 members such as YMnRMn6Sn691SnRMn6Sn692, those competing interlayer terms can drive helical or spiral phases; in moment-bearing members, Mn–RMn6Sn693 antiferromagnetic coupling and RMn6Sn694-ion anisotropy stabilize ferrimagnetism, but the strength of Mn–RMn6Sn695 binding weakens from Gd to Tb to Dy and beyond (Riberolles et al., 2021).
The high-entropy phase occupies an intermediate but distinct position in this landscape. Its RMn6Sn696 K lies between GdMnRMn6Sn697SnRMn6Sn698 at 350 K and TbMnRMn6Sn699Sn(Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn600 at 450 K. Its two spin-reorientation temperatures, 210 K and 80 K, are described as new collective effects of competing (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn601 anisotropies, and no single-(Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn602 parent shows the same cascade. Its magnetoresistance at 9 T, (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn603, is more strongly linear than in any single-(Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn604 compound, for which (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn605 at 9 T is quoted as a reference scale. The sharp MR kink at 20 T, absent in most parents, is interpreted as likely reflecting a high-field modification of Dy–Mn/Er–Mn coupling carried over from ErMn(Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn606Sn(Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn607. Its anomalous Hall conductivity per kagome layer, (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn608, lies near the weighted average of parent values (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn609–(Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn610, which is taken as evidence that topological bands survive high-entropy disorder (Liu et al., 30 Jul 2025).
The resulting physical picture is that alloying five rare-earth elements tunes the balance between in-plane and out-of-plane anisotropy and modifies Mn–(Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn611 exchange without destroying the Mn kagome backbone. In the language of the parent-series studies, rare-earth substitution functions as a magnetic knob that can tune between three-dimensional ferrimagnets, helical instabilities, and spin-reoriented phases, each with distinct transport and topological signatures (Riberolles et al., 2021). In the high-entropy material, this tuning is not achieved by moving from one end member to another, but by embedding several competing (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn612-sector tendencies within the same (Gd0.21Tb0.22Dy0.22Ho0.19Er0.16)Mn6Sn613 kagome lattice.
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