Spin Order Research Articles

π phase shift across stripes in a charge density wave system

Many strongly correlated materials are characterized by deeply intertwined charge and spin order. Besides their high superconducting transition temperatures, one of the central features of these complex patterns in cuprates is a phase shift which occurs across lines of decreased hole density. That is, when doped away from their antiferromagnetic phase, the additional charge is not distributed uniformly, but rather in ``stripes.'' The sublattices preferentially occupied by up and down spin are reversed across these stripes, a phenomenon referred to as a ``$\ensuremath{\pi}$ phase shift.'' Many of the spin-charge patterns, including the $\ensuremath{\pi}$ phase shift, are reproduced by density matrix renormalization group and quantum Monte Carlo calculations of simplified tight binding (repulsive Hubbard) models. In this paper we demonstrate that this sublattice reversal is generic by considering the corresponding phenomenon in the attractive Hubbard Hamiltonian, where a charge density wave phase forms at half filling. We introduce charge stripes via an appropriate local chemical potential; measurements of charge correlation across the resulting lines of lowered density reveal a clear $\ensuremath{\pi}$ phase.

Symmetry Constraints on Spin Order Transfer in Parahydrogen-Induced Polarization (PHIP)

It is well known that the association of parahydrogen (pH2) with an unsaturated molecule or a transient metalorganic complex can enhance the intensity of NMR signals; the effect is known as parahydrogen-induced polarization (PHIP). During recent decades, numerous methods were proposed for converting pH2-derived nuclear spin order to the observable magnetization of protons or other nuclei of interest, usually 13C or 15N. Here, we analyze the constraints imposed by the topological symmetry of the spin systems on the amplitude of transferred polarization. We find that in asymmetric systems, heteronuclei can be polarized to 100%. However, the amplitude drops to 75% in A2BX systems and further to 50% in A3B2X systems. The latter case is of primary importance for biological applications of PHIP using sidearm hydrogenation (PHIP-SAH). If the polarization is transferred to the same type of nuclei, i.e., 1H, symmetry constraints impose significant boundaries on the spin-order distribution. For AB, A2B, A3B, A2B2, AA’(AA’) systems, the maximum average polarization for each spin is 100%, 50%, 33.3%, 25%, and 0, respectively, (where A and B (or A’) came from pH2). Remarkably, if the polarization of all spins in a molecule is summed up, the total polarization grows asymptotically with ~1.27N and can exceed 2 in the absence of symmetry constraints (where N is the number of spins). We also discuss the effect of dipole–dipole-induced pH2 spin-order distribution in heterogeneous catalysis or nematic liquid crystals. Practical examples from the literature illustrate our theoretical analysis.

Role of spin-phonon and electron-phonon interactions in the phonon renormalization of (Eu1−xBix)2Ir2O7 across the metal-insulator phase transition: Temperature-dependent Raman and x-ray studies

We report temperature-dependent Raman scattering and X-ray diffraction studies of pyrochlore iridates, (Eu$_{1-x}$Bi$_x$)$_2$Ir$_2$O$_7$, for x=0, 0.02, 0.035, 0.05 and 0.1. The temperature variation in Raman experiments spans from 4 K to 300 K, covering the metal-insulator phase transition accompanied by paramagnetic to all-in/all-out (AIAO) spin ordering (T$_N$). These systems also show a Weyl semi-metal (WSM) phase at low temperatures (below ~50 K). We show that the Ir-O-Ir bond bending mode, A$_{1g}$ (510 cm$^{-1}$), shows anomalous softening in the magnetically ordered AIAO state, arising primarily from the spin-phonon interaction due to the phonon-modulation of the Dzyaloshinskii-Moriya (DM) spin-exchange interaction. The two stretching modes, T$_{2g}^1$ (307 cm$^{-1}$) and T$_{2g}^2$ (382 cm$^{-1}$) harden significantly in the magnetic insulating phase. The T$_{2g}$ phonons also show anomalous temperature dependence of their mode frequencies, hitherto unreported, due to strong electron-phonon coupling. The signatures of the WSM state are observed in phonon renormalization below 50 K due to strong electron-phonon interaction. Our experimental results establish strong magneto-elastic coupling below T$_N$ and significant electron-phonon interactions in the metallic phase above T$_N$ as well as in the low-temperature WSM state.

Spin-glass behavior and magnetocaloric properties of high-entropy perovskite oxides

The high-entropy concept has been recently proposed to be a promising paradigm to enhance the magnetocaloric properties of materials. Motivated by this, the magnetic properties and the magnetocaloric performance of two high-entropy perovskites (Dy1/4Ho1/4Er1/4Tb1/4)FeO3 and (Gd1/5Dy1/5Ho1/5Er1/5Tb1/5)FeO3 have been investigated. The magnetic measurements indicate that a spin-glass phase occurs at low temperatures in the high-entropy compounds, which is induced by the strong compositional disorder of rare-earth sublattice. The glassy state can lead to a sluggish magnetic transition and consequently a potential improvement in the magnetocaloric performance. Due to the increase in configurational entropy, large refrigerant capacity of 247 and 203 J/kg for a magnetic field change of 70 kOe is obtained in the (Gd1/5Dy1/5Ho1/5Er1/5Tb1/5)FeO3 and (Dy1/4Ho1/4Er1/4Tb1/4)FeO3 compounds, respectively. Our findings highlight the availability of spin order control through tuning the configurational entropy and demonstrate the key role of high-entropy design in enhancing the magnetocaloric properties of materials.

Extreme structure and spontaneous lift of spin degeneracy in doped perforated bilayer graphenes

Extreme structure and spin states of doped and undoped perforated bigraphenes was studied using DFT simulations. It was found that folded nanopores possess extremely high curvature of 0.34 Å−1. Dramatic structural deformation causes severe changes of the chemical properties of carbon atoms localized at the nanopores converting the folded edges to local oxidative fragments. It was found that asymmetrical coordination of either Li, Ca, or Al to the nanopores is coupled with electron transfer from metal to edge carbon atoms and breakdown of local inversion symmetry. Li-, Ca-, and Al-doped perforated AA bigraphene revealed ferromagnetic spin ordering with magnetic moments of 0.38, 0.14, and 0.32μB/unit cell, respectively, and spin polarization energy gain of 0.037eV for Ca-doped superlattice. It was shown that ferromagnetic spin ordering of bigraphene nanopores contradicts to the Nagaoka's theorem, which excludes strong electron correlations as a reason of spin polarization. Spontaneous lift of spin degeneracy was interpreted in terms of perturbing intense local electrostatic fields from extra electron charges localized at the nanopore edges, coupled with breakdown of space inversion and local translation invariances. It was shown that spin energy splitting is proportional to the matrix elements calculated on Bloch states with opposite wavevectors and perturbing electrostatic fields.

Spin and valley ordering of fractional quantum Hall states in monolayer graphene

We study spin and valley ordering in the quantum Hall fractions in monolayer graphene at Landau level filling factors ${\ensuremath{\nu}}_{G}=\ensuremath{-}2+n/3\phantom{\rule{4pt}{0ex}}(n=2,4,5)$. We use exact diagonalizations on the spherical as well as toroidal geometry by taking into account the effect of realistic anisotropies that break the spin/valley symmetry of the pure Coulomb interaction. We also use a variational method based on eigenstates of the fully $\text{SU}(4)$ symmetric limit. For all the fractions we study, there are two-component states for which the competing phases are generalizations of those occurring at neutrality ${\ensuremath{\nu}}_{G}=0$. They are ferromagnetic, antiferromagnetic, charge-density wave, and K\'ekul\'e phases, depending on the values of Ising or $XY$ anisotropies in valley space. The varying spin-valley content of the states leads to ground-state quantum numbers that are different from the ${\ensuremath{\nu}}_{G}=0$ case. For filling factor ${\ensuremath{\nu}}_{G}=\ensuremath{-}2+5/3$, there is a parent state in the $\text{SU}(4)$ limit that has a flavor content $(1,1/3,1/3,0)$ where the two components that are one-third filled form a two-component singlet. The addition of anisotropies leads to the formation of new states that have no counterpart at ${\ensuremath{\nu}}_{G}=0$. While some of them are predicted by the variational approach, we find notably that negative Ising-like valley anisotropy leads to the formation of a state that is a singlet in both spin and valley space and lies beyond the reach of the variational method. Also fully spin polarized two-component states at $\ensuremath{\nu}=\ensuremath{-}2+4/3$ and $\ensuremath{-}2+5/3$ display an emergent $\text{SU}(2)$ valley symmetry because they do not feel point-contact anisotropies. We discuss implications for current experiments concerning possible spin transitions.

Magnetoelectric coupling in Sr3Co2Fe23.04Al0.96O41 single crystal near room temperature

We have grown Z-type hexaferrite Sr3Co2Fe23.04Al0.96O41 single crystal with a little Al3+ ion doping on the Fe3+ ion sites by the Na2CO3-Fe2O3 flux method. The magnetic properties and magnetoelectric (ME) coupling effects were investigated systematically. With Al3+ ion doping, the transverse conical magnetic phase could be maintained up to 359 K under small magnetic field (H). The magnetization increases with two steps to saturation at 300 K as shown in the M-H curve, implying the existence of a spiral spin order. The ME coupling effects occur near room temperture. Besides, the sign of the electric polarization (P) is independent of the H and the intensity of the electric polarization changes without any decays at 200 K under the oscillating magnetic field. Both of them are crucial for device application, such as information storage devices and non-volatile memory.

Carrier Doping Physics of Rare Earth Perovskite Nickelates RENiO3

The family of rare earth (RE) nickelate perovskites RENiO3 has emerged over the past two decades as an important platform for quantum matter physics and advanced applications. The parent compounds from this family are strongly correlated insulators or metals, in most cases with long-range spin order. In the past few years, carrier doping has been achieved using different approaches and has been proven to be a powerful tuning parameter for the microscopic properties and collective macroscopic states in RENiO3 compounds. In particular, a series of recent studies has shown that carrier doping can be responsible for dramatic but reversible changes in the long-range electronic and magnetic properties, underscoring the potential for use of nickelates in advanced functional devices. In this review, we discuss the recent advancements in our description, understanding and application of electron-doped rare earth nickelates. We conclude with a discussion of the developments and outlook for harnessing the quantum functional properties of nickelates in novel devices for sensing and neuromorphic computation.

A -site Mn2+ tuned magnetism and electrical transport properties in the transition-metal-only perovskite oxide MnCu3Mn4O12

An $A{A}_{3}^{\ensuremath{'}}{B}_{4}{\mathrm{O}}_{12}$-type transition-metal-only quadruple perovskite oxide $\mathrm{Mn}{\mathrm{Cu}}_{3}{\mathrm{Mn}}_{4}{\mathrm{O}}_{12}$ was prepared by high-pressure and high-temperature methods. The compound has a cubic $Im$-3 symmetry with charge distribution of ${\mathrm{Mn}}^{2+}{\mathrm{Cu}}_{3}^{2+}{\mathrm{Mn}}_{4}^{4+}{\mathrm{O}}_{12}$. A long-range ferrimagnetic phase transition caused by ${\mathrm{Cu}}^{2+}(\ensuremath{\uparrow}){\mathrm{Mn}}^{4+}(\ensuremath{\downarrow})$ spin interaction is found to occur at a Curie temperature ${T}_{\mathrm{C}}\ensuremath{\approx}365\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ . Different from the isostructural compound $\mathrm{Ca}{\mathrm{Cu}}_{3}{\mathrm{Mn}}_{4}{\mathrm{O}}_{12}$, the susceptibility of $\mathrm{Mn}{\mathrm{Cu}}_{3}{\mathrm{Mn}}_{4}{\mathrm{O}}_{12}$ experiences a second anomaly \ensuremath{\sim}200 K due to the effects of $A$-site ${\mathrm{Mn}}^{2+}$ spin ordering. Moreover, the $A$-site ${\mathrm{Mn}}^{2+}$ spins also considerably decrease the magnitude of resistivity. Theoretical calculations reveal that the $A$-site Mn $3d$ orbitals locate near the Fermi level and hybridize with the Cu $3d$ and O $2p$ orbitals, playing a crucial role on the magnetic and electrical transport properties of $\mathrm{Mn}{\mathrm{Cu}}_{3}{\mathrm{Mn}}_{4}{\mathrm{O}}_{12}$. In this paper, we provide an interesting example using $A$-site magnetic ions to significantly tune the physical properties in $A{A}_{3}^{\ensuremath{'}}{B}_{4}{\mathrm{O}}_{12}$-type quadruple perovskite oxides.

First-principles study of magnetic states and the anomalous Hall conductivity of MNb3S6 (M=Co,Fe,Mn, and Ni)

Inspired by the observation of the extremely large anomalous Hall effect in the absence of applied magnetic fields or uniform magnetization in ${\mathrm{CoNb}}_{3}{\mathrm{S}}_{6}$ [Nat. Commun. 9, 3280 (2018); Phys. Rev. Research 2, 023051 (2020)], we perform a first-principles study of this and related compounds of the $M{\mathrm{Nb}}_{3}{\mathrm{S}}_{6}$ type with different transition metal $M$ ions to determine their magnetic orders and the anomalous Hall conductivity (AHC). We find that noncoplanar antiferromagnetic ordering is favored relative to collinear or coplanar order in the case of $M$ = Co, Fe, and Ni, while ferromagnetic ordering is favored in ${\mathrm{MnNb}}_{3}{\mathrm{S}}_{6}$ at low temperatures. The AHC in these materials with noncoplanar spin ordering can reach about ${e}^{2}/h$ per crystalline layer, while being negligible for coplanar and collinear cases. We also find that the AHC depends sensitively on doping and reaches a maximum for intermediate values of the local spin exchange potential between 0.3 and 0.8 eV. Our AHC results are consistent with the reported Hall measurements in ${\mathrm{CoNb}}_{3}{\mathrm{S}}_{6}$ and suggest a possibility of similarly large anomalous Hall effects in related compounds.

Nonthermal breaking of magnetic order via photogenerated spin defects in the spin-orbit coupled insulator Sr3Ir2O7

In Mott insulators the evolution of antiferromagnetic order to superconducting or charge-density-wave-like states upon chemical doping underpins the control of quantum phases. Photo-doping can induce similar transitions on the ultrafast timescale, however the response of the spin system has remained elusive. Here, we use 4D-ultrafast optical spectroscopy to extract quantitative magnetic dynamics in the spin-orbit coupled Mott insulator Sr3Ir2O7. We demonstrate that light can non-thermally melt long-range spin order. At low fluences magnetic order recovers within 1 ps despite demagnetization of roughly 50%. However, high fluences induce a crossover to a long-lived demagnetized state without increasing the lattice temperature. We show that the generation of photo-induced spin defects enables a mechanism that stabilizes the demagnetized state which could help expose new transient phases.

Observation of Short‐Period Helical Spin Order and Magnetic Transition in a Nonchiral Centrosymmetric Helimagnet

AbstractThe search for materials exhibiting nanoscale spiral order continues to be fuelled by the promise of emergent inductors. Although such spin textures have been reported in many materials, most of them exhibit long periods or are limited to operate far below room temperature. Here, the real‐space observation of an ordered helical spin order with a period of 3.2 nm in a nonchiral centrosymmetric helimagnet MnCoSi at room temperature via multiangle and multiazimuth approach of Lorentz transmission electron microscopy (TEM) is presented. A magnetic transition from the ordered helical spin order to a cycloidal spin order below 228 K is clearly revealed by in situ neutron powder diffraction and Lorentz TEM, which is closely correlated with temperature‐induced variation in magneto‐crystalline anisotropy. These results reveal the origin of spiral ordered spin textures in nonchiral centrosymmetric helimagnet, which can serve as a new strategy for searching materials with nanoscale spin order with potential applications in emergent electromagnetism.

Strong anisotropic Hall effect in single-crystalline CeMn2Ge2 with helical spin order

The topological Hall effect (THE) is an emergent magnetotransport phenomena in noncollinear itinerant magnets, and has been extensively studied in magnetic materials hosting skyrmion lattices and geometrically frustrated lattices. To explore THE in materials with new nontrivial spin textures, we investigate the anisotropic Hall effect in a longitudinal conical-ordered magnet ${\mathrm{CeMn}}_{2}{\mathrm{Ge}}_{2}$ crystallized in ${\mathrm{ThCr}}_{2}{\mathrm{Si}}_{2}$-type structure, which has a spiral magnetic propagation vector along the $c$ axis and a helical component in the $ab$ plane. Magnetic susceptibility reveals it undergoes two magnetic transitions at \ensuremath{\sim}394 and \ensuremath{\sim}318 K; the latter corresponds to the antiferromagnetic to conical spin order transition in the magnetic Mn lattices. For applied field $({\ensuremath{\mu}}_{0}H)$ along the $c$ axis, ${\mathrm{CeMn}}_{2}{\mathrm{Ge}}_{2}$ exhibits conventional anomalous Hall effect with large intrinsic Hall conductivity ${\ensuremath{\sigma}}_{xy}^{\mathrm{int}}\ensuremath{\sim}276\phantom{\rule{0.28em}{0ex}}{\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$ but no THE responses. A large THE is realized as ${\ensuremath{\mu}}_{0}H$ is oriented within the $ab$ plane due to a field-induced noncoplanar spin texture with scalar spin chirality. Moreover, room temperature (RT) angle-dependent Hall effect measurements reveal the THE emerges when the field is applied nonparallel to the $c$ axis and it reaches maximal value for ${\ensuremath{\mu}}_{0}H$ when it is tilted close to the $ab$ plane with a canting angle of \ensuremath{\sim}15\ifmmode^\circ\else\textdegree\fi{}, at which large topological Hall conductivity of $\ensuremath{\sim}43\phantom{\rule{0.28em}{0ex}}{\mathrm{\ensuremath{\Omega}}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$ is detected. Our results demonstrate a RT anisotropic THE and its tunability by the application of a tilted magnetic field in conical-ordered magnets, making a step forward for designing spintronic devices based on THE.

Light bending from eikonal in worldline quantum field theory

Using the worldline quantum field theory (WQFT) formalism for classical scattering, we study the deflection of light by a heavy massive spinless/spinning object. WQFT requires the use of the worldline dressed propagator of a photon in a gravitational background, which we construct from first principles. The action required to set up the worldline path integral is constructed using auxiliary variables, which describe dynamically the spin degrees of freedom of the photon and take care of path ordering. We test the fully regulated path integral by recovering the photon-photon-graviton vertex. With the dressed propagator at hand, we follow the WQFT procedure by setting up the partition function and deriving the Feynman rules which can be used to evaluate it perturbatively. These rules depend on the auxiliary variables. The latter ultimately do not contribute in the geometric-optics regime, which realizes the equivalence between the scattering of a photon and a massive scalar with that of a massless and a massive scalar. Then, the calculation of the eikonal phase and the deflection angle simplifies considerably. Using the eikonal phase defined in terms of the partition function, we calculate explicitly the deflection angle at NLO in the spinless case, and at LO in the spinning case up to quadratic order in spin.

Reentrant ferroelectric phase induced by a tilting high magnetic field in Ni3V2O8

The canonical multiferroic material ${\mathrm{Ni}}_{3}{\mathrm{V}}_{2}{\mathrm{O}}_{8}$ with a kagome staircase structure of $S=1\phantom{\rule{0.16em}{0ex}}{\mathrm{Ni}}^{2+}$ spins has attracted much attention for its complex magnetic phase diagram, as well as the interplay between spin orders and ferroelectricity. In the present work, we report a comprehensive angular dependent ferroelectric polarization study on ${\mathrm{Ni}}_{3}{\mathrm{V}}_{2}{\mathrm{O}}_{8}$ with the field rotating within the $ac$ plane at low temperatures. The low field induced ferroelectric (LF) state along the crystallographic $b$ axis, which has been observed when the field is applied parallel to the easy axis ($a$ axis), is revealed to vanish suddenly as the field is rotating close to the $c$ axis. Of particular interest is the observation of the reentrant ferroelectric (HF) phase at high field for various orientations when the field is between the $a$ and $c$ axes within a small angle range. The field-angle phase diagrams are built based on the low-temperature angular dependent polarization results and composed of a continuous LF phase and a discontinuous HF phase both exhibiting symmetry with respect to the $a$ axis. The microscopic origins of the two phases are different due to the two decoupled sublattices in the kagome staircase structure, where the low-field polarization is proposed to originate from the spiral structure of the spine spins, while the high-field phase is ascribed to the ordering of the cross-ties under a tilting high magnetic field.

Study of magnetic and magnetocaloric effect of REMnO3(RE=Dy,Eu)manganites

We have systematically investigated the magnetic and magnetocaloric effect (MCE) of REMnO3 (RE = Dy, Eu) manganites sintered by solid-state reaction method. The Neel temperature (TN), the maximum magnetic entropy change (-ΔSmmax) and the relative cooling power (RCP) of the sample were obtained by measuring the magnetization and heat capacity. Under the magnetic field change of 50 kOe, large -ΔSmmax of 8.93J/kg K and 9.31J/kg K are achieved around the TN of 14 K and 50 K for DyMnO3 and EuMnO3, respectively. It is proved by the slope of the Arrott plot and the universal phenomenological curve that the sample undergoes second order phase transition. The critical behavior of antiferromagnetic to paramagnetic phase transition is studied by modifying Arrott plot, which shows that the spin order of the sample decreases at the phase transition temperature and tends to change into shortrange order. The large magnetic entropy change calculated by Landau theory and experimental data indicates that the sample has a large magnetocaloric effect and has potential application in low temperature magnetic refrigeration materials.

Zoology of Multiple-Q Spin Textures in a Centrosymmetric Tetragonal Magnet with Itinerant Electrons.

Magnetic skyrmion is a topologically stable particle‐like swirling spin texture potentially suitable for high‐density information bit, which was first observed in noncentrosymmetric magnets with Dzyaloshinskii–Moriya interaction. Recently, nanometric skyrmion has also been discovered in centrosymmetric rare‐earth compounds, and the identification of their skyrmion formation mechanism and further search of nontrivial spin textures are highly demanded. Here, magnetic structures in a prototypical skyrmion‐hosting centrosymmetric tetragonal magnet GdRu2Si2 is exhaustively studied by performing the resonant X‐ray scattering experiments. A rich variety of double‐Q magnetic structures, including the antiferroic order of meron(half‐skyrmion)/anti‐meron‐like textures with fractional local topological charges are identified. The observed intricate magnetic phase diagram is successfully reproduced by the theoretical framework considering the four‐spin interaction mediated by itinerant electrons and magnetic anisotropy. The present results will contribute to the better understanding of the novel skyrmion formation mechanism in this centrosymmetric rare‐earth compound, and suggest that itinerant electrons can ubiquitously host a variety of unique multiple‐Q spin orders in a simple crystal lattice system.

Berezinskii-Kosterlitz-Thouless transition transport in spin-triplet superconductor

As the spin-triplet superconductivity arises from the condensation of spinful Cooper pairs, its full characterization requires not only charge ordering, but also spin ordering. For a two-dimensional (2D) easy-plane spin-triplet superconductor, this na\"{i}vely seems to suggest the possibility of two distinct Berezinskii-Kosterlitz-Thouless (BKT) phase transitions, one in the charge sector and the other in the spin sector. However, it has been recognized that there are actually three possible BKT transitions, involving the deconfinement of, respectively, the conventional vortices, the merons and the half-quantum vortices with vorticity in both the charge and the spin current. By considering equal-spin-pairing spin-triplet superconductors with bulk spin degeneracy, we show how all the transitions can be characterized by the relation between the voltage drop and the spin-polarized current bias. This study reveals that, due to the hitherto unexamined transport of half-quantum vortices, there is an upper bound on the spin supercurrent in a quasi-long range ordered spin-triplet superconductor, which provides a means for half-quantum vortex detection via transport measurements and deeper understanding of fluctuation effects in superconductor-based spintronic devices.

Interplay of lattice, spin, and dipolar properties in CoTeMoO6 : Emergence of Griffiths-like phase, metamagnetic transition, and magnetodielectric effect

The physical properties of the noncentrosymmetric and quasi-two-dimensional canted antiferromagnetic material ${\mathrm{CoTeMoO}}_{6}$ (CTMO) are studied. We unravel a spectrum of intriguing phenomena, including a correlated short-range-ordered Griffiths-like phase near ${T}_{G}\ensuremath{\sim}64\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, a sharp step-like metamagnetic behavior of isothermal magnetization induced by a spin-flop transition at a critical magnetic field ${H}_{\mathrm{c}}\ensuremath{\sim}1.2\phantom{\rule{0.16em}{0ex}}\mathrm{T}$, a strong dielectric anomaly, a pronounced magnetodielectric effect, and the associated weak magnetoelectric coupling at its magnetic transition temperature, ${T}_{N}\ensuremath{\sim}23.4\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The crucial roles played by spin canting in CTMO are revealed in the aforementioned strongly entangled behavior of the spin and dipolar order parameters. The observed magnetostriction effect coupled with spin-phonon coupling seems to be a key factor in influencing the observed magnetodielectric effect. In addition, our theoretical first-principles calculations predict an insulating state with a canted antiferromagnetic spin configuration that matches well with the experimental results.

FeMn3Ge2Sn7O16: A Perfectly Isotropic 2-D Kagomé Lattice that Breaks Magnetic Symmetry with Partial Spin Order

FeMn₃Ge₂Sn₇O₁₆: A Perfectly Isotropic 2-D Kagomé Lattice that Breaks Magnetic Symmetry with Partial Spin Order