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We propose an improved tensor renormalization group (TRG) algorithm, the bond-weighted TRG (BTRG). In BTRG, we generalize the conventional TRG by introducing bond weights on the edges of the tensor network. We show that BTRG outperforms the conventional TRG and the higher-order tensor renormalization group with the same bond dimension, while its computation time is almost the same as that of TRG. Furthermore, BTRG can have non-trivial fixed-point tensors at an optimal hyperparameter. We demonstrate that the singular value spectrum obtained by BTRG is invariant under the renormalization procedure in the case of the two-dimensional Ising model at the critical point. This property indicates that BTRG performs the tensor contraction with high accuracy while keeping the scale-invariant structure of tensors., 5 pages, 6 figures. +Supplemental Material

Search for a new quantum state of matter emerging in a crystal is one of recent trends in condensed matter physics. For magnetic materials, geometrical frustration and high magnetic field are two key ingredients to realize it: a conventional magnetic order is possibly destroyed by competing interactions (frustration) and is replaced by an exotic state that is characterized in terms of quasiparticles, that are magnons, and the magnetic field can control the density and chemical potential of the magnons. Here we show that a synthetic copper mineral, Cd-kapellasite, comprising a kagome lattice made of corner-sharing triangles of Cu2+ ions carrying spin-1/2 exhibits an unprecedented series of fractional magnetization plateaux in ultrahigh magnetic fields up to 160 T, which may be interpreted as crystallizations of emergent magnons localized on the hexagon of the kagome lattice. Our observation reveals a novel type of particle physics realized in a highly frustrated magnet., Comment: 9 pages, 10 figures

Purpose: We performed and analyzed the DFI test and semen test based on the WHO criteria and compared the two using semen factors. Methods: DFI tests and general semen tests were conducted in accordance with the WHO criteria, and correlations between the two tests were investigated. The WHO criteria were set as the cutoff value for each of the following factors: fluid volume, concentration, motility, and normal morphology, and compared with the DFI results.Results: The subjects had a mean DFI of 15.6±11.5% and the DFI increased with age. In contrast, the concentration, motility, and normal morphology decreased as the DFI increased. Patients who satisfied the WHO criteria in terms of sperm concentration, motility, and normal morphology had a significantly lower DFI than the group that did not satisfy the criteria. Therefore, evaluation with a general semen test based on the WHO criteria should be regarded as a qualitative evaluation of all factors other than fluid volume.Conclusions: Male infertility due to sperm DNA fragmentation should be suspected when in vitro fertilization (IVF) results are poor despite normal semen findings based on the WHO criteria. The results of this study suggest that the DFI test may be an important evaluation in follow-up semen analyses.

TeNeS (Tensor Network Solver) is a free/libre open-source software program package for calculating two-dimensional many-body quantum states based on the tensor network method and the corner transfer matrix renormalization group (CTMRG) method. This package calculates ground-state wavefunctions for user-defined Hamiltonians and evaluates user-defined physical quantities such as magnetization and correlation functions. For certain predefined models and lattices, there is a tool that makes it easy to generate input files. TeNeS uses an OpenMP/MPI hybrid parallelized tensor operation library and thus can perform large-scale calculations using massively parallel machines., Comment: 16 pages, 10 figures

In this article, we present a high performance, portable and well templated implementation for computing and fast-updating Pfaffian and inverse of an even-ranked skew-symmetric (antisymmetric) matrix. It is achieved with a skew-symmetric, blocked variant of the Parlett-Reid algorithm and a blocked update scheme based on the Woodbury matrix identity. Installation of this framework into the geminal-wavefunction-based many-variable Variational Monte Carlo (mVMC) code boosts sampling performance to up to more than $6$ times without changing Markov chain's behavior. The implementation is based on an extension of the BLAS-like instantiation software (BLIS) framework which has optimized kernel for many state-of-the-art processors including Intel Skylake-X, AMD EPYC Rome and Fujitsu A64FX., Comment: 18 pages, 3 figures and 3 tables. Source code presented in this work can be obtained from http://github.com/issp-center-dev/mVMC/tree/develop

We propose a new tensor renormalization group algorithm, Anisotropic Tensor Renormalization Group (ATRG), for lattice models in arbitrary dimensions. The proposed method shares the same versatility with the Higher-Order Tensor Renormalization Group (HOTRG) algorithm, i.e., it preserves the lattice topology after the renormalization. In comparison with HOTRG, both of the computation cost and the memory footprint of our method are drastically reduced, especially in higher dimensions, by renormalizing tensors in an anisotropic way after the singular value decomposition. We demonstrate the ability of ATRG for the square lattice and the simple cubic lattice Ising models. Although the accuracy of the present method degrades when compared with HOTRG of the same bond dimension, the accuracy with fixed computation time is improved greatly due to the drastic reduction of the computation cost., 6 pages, 9 figures

Background: Diclofenac inhibits follicle rupture and its use in natural-cycle in vitro fertilization and embryo transfer (IVF-ET) has been reported to increase oocyte retrieval chances but has not been reported to improve the therapeutic outcome (live birth). The question is whether the therapeutic utility of diclofenac is demonstrable when administered to a subgroup of women with an imminent LH surge, a higher risk group for premature ovulation.Methods: Infertile women indicated for the natural-cycle IVF-ET between September 2014 and February 2015 (n=183) were recruited in a private infertility clinic and diclofenac use (50 mg suppositories, thrice every 8 h before oocyte retrieval) was offered when their serum LH level was ≥14.0 IU/L on an LH-triggering day (n=137). Of the 137 women, 108 electively used diclofenac and 29 did not. Oocytes were retrieved from both dominant and subordinate nondominant follicles and were fertilized. The resulting blastocysts were frozen, thawed, and transferred one by one in the following spontaneous ovulatory or hormone replacement cycles. Results: Cumulative live birth rate (after the single oocyte retrieval) was calculated from the dominant and nondominant follicles. The live birth rate from dominant follicles was higher in the diclofenac group (21/108, 19%) than in the no diclofenac group (1/29, 3%) (P < .05). Conversely, the live birth rate from nondominant follicles, which had no potential for ovulation, was not different between the diclofenac group (13/108, 12%) and the no diclofenac group (3/29, 10%). Conclusion: Diclofenac improved the live birth rate from dominant follicles when it was administered to women with an imminent LH surge. However, diclofenac did not affect the live birth rate from non-dominant follicles which were not at risk of follicle rupture.

We performed inelastic neutron scattering measurements on a polycrystalline sample of a classical kagome antiferromagnet ${\mathrm{NaBa}}_{2}{\mathrm{Mn}}_{3}{\mathrm{F}}_{11}$ to investigate the possibility of a dispersionless zero-energy excitation associated with rotation of spins along the chains. The observed spectra indeed exhibit such an excitation with strong intensity at low energy, as well as dispersive excitations with weak intensity at high energy. Combining the measurements with calculations from linear spin-wave theory reveals that ${\mathrm{NaBa}}_{2}{\mathrm{Mn}}_{3}{\mathrm{F}}_{11}$ is a good realization of the classical kagome antiferromagnet which exhibits a dispersionless mode lifted by the magnetic dipole-dipole interaction.

Motivated by the recent theoretical study by Okubo $et \ al$ [Phys. Rev. Lett. ${\bf 108}$, 017206 (2012)] on the possible realization of the frustration-induced $ symmetric$ skyrmion-lattice state in the $J_1$-$J_2$ (or $J_1$-$J_3$) triangular-lattice Heisenberg model without the Dzyaloshinskii-Moriya interaction, we investigate the ordering of the classical $J_1$-$J_2$ honeycomb-lattice Heisenberg antiferromagnet under magnetic fields by means of a Monte Carlo simulation, a mean-field analysis and a low-temperature expansion. The model has been known to have an infinite ring-like degeneracy in the wavevector space in its ground state for $1/6

We provide a framework for understanding the gapless Kitaev spin liquid (KSL) in the language of tensor network(TN). Without introducing Majorana fermion, most of the features of the KSL including the symmetries, gauge structure, criticality and vortex-freeness are explained in a compact TN representation. Our construction reveals a hidden string gas structure of the KSL. With only two variational parameters to adjust, we obtain an accurate KSL ansatz with the bond dimension D = 8 in a compact form, where the energy is about 0.007% higher than the exact one. In addition, the opening of gap and non-Abelian phase driven by a magnetic field are naturally understood in our construction.

Recent discovery of the half quantized thermal Hall conductivity in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document}α-RuCl\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${}_{3}$$\end{document}3, a candidate material for the Kitaev spin liquid, suggests the presence of a highly entangled quantum state in external magnetic fields. This field induced phase appears between the low field zig-zag magnetic order and the high field polarized state. Motivated by this experiment, we study possible field induced quantum phases in theoretical models of the Kitaev magnets, using the two dimensional tensor network approach or infinite tensor product states. We find various quantum ground states in addition to the chiral Kitaev spin liquid occupying a small area in the phase diagram. They form a band of emergent quantum phases in an intermediate window of external magnetic fields, somewhat reminiscent of the experiment. We discuss the implications of these results in view of the experiment and previous theoretical studies., \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\alpha$$\end{document}α-RuCl\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${}_{3}$$\end{document}3 is a candidate Kitaev spin liquid but whether or not this is realised depends on the details of the magnetic interactions. Here, the authors use state-of-the-art numerical methods to predict that for a large parameter region the Kitaev phase is supplanted by nematic paramagnetic phases.

Cytogenetic analysis of the retained products of conception (POC) is the most effective test for identifying miscarriage causes. However, there has been no large-scale study limited to blastocyst transfer. This study retrospectively reports the findings of 1030 cases in which POC analysis was performed after missed abortion following single blastocyst transfer performed at the Shinbashi Yume Clinic. We identified 19.4% as normal karyotypes and 80.6% as aneuploid. These cases broke down into: 62.3% trisomy; 7.8% double trisomy; 0.5% triple or quadruple trisomy; 1.3% monosomy 21; 3.2% monosomy X; 0.1% 47,XXY; 1.0% polyploidy; 1.0% mixed; 1.1% embryonic mosaicism; and 2.4% structural anomalies. In samples with normal karyotypes, 49.5% were female while 50.5% were male. The occurrence of trisomy and double trisomy were both significantly more frequent in the ≥38 years group than in the ≤37 years group (P < 0.01). Trisomy was significantly more frequently associated with fetal heartbeat (P < 0.01); double trisomy, polyploidy and normal karyotype were significantly more frequent with no fetal heartbeat (P < 0.01). There was no significant difference in the frequency of chromosomal abnormalities between the number of miscarriages or blastocyst quality. Thus, POC cytogenetic testing is highly valuable for ascertaining the cause of miscarriage.

We provide new insights into the Abelian and non-Abelian chiral Kitaev spin liquids on the star lattice using the recently proposed loop gas (LG) and string gas states [Lee, Kaneko, Okubo, and Kawashima, Phys. Rev. Lett. 123, 087203 (2019)]. Those are compactly represented in the language of the tensor network. By optimizing only one or two variational parameters, accurate ansatze are found in the whole phase diagram of the Kitaev model on the star lattice. In particular, the variational energy of the LG state becomes exact (within machine precision) at two limits in the model, and the criticality at one of those is analytically derived from the LG feature. It reveals that the Abelian chiral spin liquids (CSLs) are well demonstrated by the short-ranged LG whereas the non-Abelian CSLs are adiabatically connected to the critical LG where the macroscopic loops appear. Furthermore, by constructing the minimally entangled states and exploiting their entanglement spectrum and entropy, we identify the nature of anyons and the chiral edge modes in the non-Abelian phase with the Ising conformal field theory.

We haved studied the ground state of the classical kagome antiferromagnet ${\mathrm{NaBa}}_{2}{\mathrm{Mn}}_{3}{\mathrm{F}}_{11}$. Strong magnetic Bragg peaks observed for $d$ spacings shorter than 6.0 \AA{} were indexed by the propagation vector of ${\mathbit{k}}_{0}=(0,0,0)$. Additional peaks with weak intensities in the $d$-spacing range above 8.0 \AA{} were indexed by the incommensurate vector of ${\mathbit{k}}_{1}=[0.3209(2),0.3209(2),0]$ and ${\mathbit{k}}_{2}=[0.3338(4),0.3338(4),0]$. Magnetic structure analysis unveils a ${120}^{\ensuremath{\circ}}$ structure with the tail-chase geometry having ${\mathbit{k}}_{0}$ modulated by the incommensurate vector. A classical calculation of the Heisenberg kagome antiferromagnet with antiferromagnetic second-neighbor interaction, for which the ground state a ${\mathbit{k}}_{0}\phantom{\rule{4pt}{0ex}}{120}^{\ensuremath{\circ}}$ degenerated structure, reveals that the magnetic dipole-dipole (MDD) interaction including up to the fourth neighbor terms selects the tail-chase structure. The observed modulation of the tail-chase structure is attributed to a small perturbation such as the long-range MDD interaction or the interlayer interaction.

We investigate the ground state properties of ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ based on numerical calculations of the recently proposed ab initio Hamiltonian represented by Kitaev and extended Heisenberg interactions. To overcome the limitation posed by small tractable system sizes in the exact diagonalization study employed in a previous study [Y. Yamaji et al., Phys. Rev. Lett. 113, 107201 (2014)], we apply a two-dimensional density matrix renormalization group and an infinite-size tensor-network method. By calculating at much larger system sizes, we critically test the validity of the exact diagonalization results. The results consistently indicate that the ground state of ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ is a magnetically ordered state with zigzag configuration in agreement with experimental observations and the previous diagonalization study. Applications of the two independent methods in addition to the exact diagonalization study further uncover a consistent and rich phase diagram near the zigzag phase beyond the accessibility of the exact diagonalization. For example, in the parameter space away from the ab initio value of ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ controlled by the trigonal distortion, we find three phases: (i) an ordered phase with the magnetic moment aligned mutually in 120 degrees orientation on every third hexagon, (ii) a magnetically ordered phase with a 16-site unit cell, and (iii) an ordered phase with presumably incommensurate periodicity of the moment. It suggests that potentially rich magnetic structures may appear in ${A}_{2}{\mathrm{IrO}}_{3}$ compounds for $A$ other than Na. The present results also serve to establish the accuracy of the first-principles approach in reproducing the available experimental results thereby further contributing to finding a route to realize the Kitaev spin liquid.

The spin-1 Haldane chain is an example of the symmetry-protected-topological (SPT) phase in one dimension. Experimental realization of the spin chain materials usually involves both the uniaxial-type, $D(S^z)^2$, and the rhombic-type, $E[(S^x)^2-(S^y)^2]$, single-ion anisotropies. Here, we provide a precise ground-state phase diagram for spin-1 Haldane chain with these single-ion anisotropies. Using quantum numbers, we find that the $\mathbb{Z}_2$ symmetry breaking phase can be characterized by double degeneracy in the entanglement spectrum. Topological quantum phase transitions take place on particular paths in the phase diagram, from the Haldane phase to the Large-$E_x$, Large-$E_y$, or Large-$D$ phases. The topological critical points are determined by the level spectroscopy method with a newly developed parity technique in the density matrix renormalization group [Phys. Rev. B 86, 024403 (2012)], and the Haldane-Large-$D$ critical point is obtained with an unprecedentedly precision, $(D/J)_c=0.9684713(1)$. Close to this critical point, a small rhombic single-ion anisotropy $|E|/J\ll1$ can destroy the Haldane phase and bring the system into a $y$-N\'eel phase. We propose that the compound [Ni(HF$_2$)(3-Clpy)$_4$]BF$_4$ is a candidate system to search for the $y$-N\'eel phase., Comment: Supplemental Material is included

Novel magnetic phases are expected to occur in highly frustrated spin systems. Here, we study the structurally perfect kagome antiferromagnet $\mathrm{CdC}{\mathrm{u}}_{3}{(\mathrm{OH})}_{6}{({\mathrm{NO}}_{3})}_{2}\ifmmode\cdot\else\textperiodcentered\fi{}{\mathrm{H}}_{2}\mathrm{O}$ by magnetization, magnetic torque, and heat capacity measurements using single crystals. An antiferromagnetic order accompanied by a small spontaneous magnetization that surprisingly is confined in the kagome plane sets in at ${T}_{\mathrm{N}}\ensuremath{\sim}4\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, well below the nearest-neighbor exchange interaction $J/{k}_{\mathrm{B}}=45\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. This suggests that a unique ``$\mathbf{q}=0$'' type ${120}^{\ensuremath{\circ}}$ spin structure with ``negative'' (downward) vector chirality, which breaks the underlying threefold rotational symmetry of the kagome lattice and thus allows a spin canting within the plane, is exceptionally realized in this compound rather than a common one with ``positive'' (upward) vector chirality. The origin is discussed in terms of the Dzyaloshinskii-Moriya interaction.

We have investigated how the bandwidth and sensitivity change by thickening the PZT diaphragm by simulation, and confirmed that those are improved than a general thin diaphragm. In this study, we expect the existence of an appropriate value of the aspect ratio defined between the width and the thickness. We investigate the reception performance of diaphragm transducers consisting of PZT and Si layer by FEM simulation. Design parameter dependence of the ultrasonic reception performance is confirmed by simulation, and its tendency is analyzed. Based on the results, we derive a transducer design method for a desired frequency band. A diaphragm thicker than a certain thickness threshold has a specific bandwidth of 150% or more. The critical thickness is determined by the aspect ratio. A thick diaphragm, that is, a high aspect ratio diaphragm causes coexistence of membrane vibration and thickness vibration. If the thickness is too thick, it becomes a simple vibration of the thickness vibration, and the bandwid...

We demonstrated the diaphragm type PZT oscillator performance through simulation experiments. To achieve the desired frequency, firstly, the size of a diaphragm and a thickness of PZT and Si layers are optimized. Then, we select three different PZT/Si models. Finally, we analyze the models transmission efficiency, receiving sensitivity (piezoelectric voltage / electric charge) and frequency bandwidth using an FEM simulator. The remarkable finding is that the receiving frequency bandwidth of the proposed model is much wider than a typical one. In addition, we confirmed a superiority and a future task in consideration of producing a piezoelectric micromachined ultrasonic transducer (pMUT) array.

Geometric frustration, in which competing interactions give rise to degenerate ground states, potentially induces various exotic quantum phenomena in magnetic materials. Minimal models comprising triangular units, such as triangular and Kagome lattices, have been investigated for decades to realize novel quantum phases, such as quantum spin liquid. A pentagon is the second-minimal elementary unit for geometric frustration. The realization of such systems is expected to provide a distinct platform for studying frustrated magnetism. Here, we present a spin-1/2 quantum pentagonal lattice in the new organic radical crystal α-2,6-Cl2-V [=α-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl]. Its unique molecular arrangement allows the formation of a partially corner-shared pentagonal lattice (PCPL). We find a clear 1/3 magnetization plateau and an anomalous change in magnetization in the vicinity of the saturation field, which originate from frustrated interactions in the PCPL.

For high performance piezoelectrics, few technology options are currently available. Recent studies projected a novel sound pressure sensor [1][2] using a ferroelectrics-gated FET [3], but few were reported with an evident observation. In this study, we propose a structure possessing direct coupling of a PZT to a gate of a MOS-FET (PZT-FET). A minimum detectable sound pressure, a dynamic range and a -6 dB specific bandwidth is measured by experiments, and it was proved that the former two characteristics are improved against the current typical medical ultrasound transducer.

Random dense packing of binary hard discs generated under the infinitesimal gravity protocol is investigated by a Monte Carlo simulation in the entire region of the size ratio and the concentration. When the size difference of the two species is small, the packing fraction of disc assembly becomes lower than that of the monodisperse system. Defining the adjacent neighbours of a disc through the radical tessellation, we show that the packing fraction can be related to the distance of adjacent discs and that the suppressed packing fraction is caused by an increase of the adjacent neighbours which are not seen in the monodisperse system.

症例は60歳,女性.検診で便潜血陽性を指摘され来院.血液検査にて貧血(Hb 9.4g/dl)が認められたが経口摂取可能であった.注腸造影検査にて上行結腸に閉塞像が認められたが腹部レントゲン検査ではイレウス像は認められなかった.大腸内視鏡検査では上行結腸に全周性の陥凹性病変が認められ生検にてGroup4, suspicious of adenocarcinomaであった.腹部CT検査では肝S5にlow density areaが認められ,上行結腸癌・肝転移と診断し手術施行した.開腹すると上行結腸は回腸を巻き込み一塊となり回腸への浸潤・交通が疑われ,回腸合併切除の結腸右半切除術,肝転移巣に対してラジオ波焼灼術を施行.肉眼的には癌巣は回腸への浸潤・瘻孔形成を認め,組織学的には高分化型腺癌, si, ly1, v2, n (-)であった.結腸癌による小腸結腸瘻形成例は比較的稀で,われわれが検索しえた本邦報告例は現在まで自験例を含めて36例であり,若干の文献的考察を加え報告した.

The $\mathrm{SU}(N)$ symmetric antiferromagnetic Heisenberg model with multi-column representations on the two-dimensional square lattice is investigated by quantum Monte Carlo simulations. For the representation of Young diagram with two columns, we confirm that a valence-bond solid order appears as soon as the N\'eel order disappears at $N = 10$ indicating no intermediate phase. In the case of the representation with three columns, there is no evidence for both of the N\'eel and the valence-bond solid ordering for $N\ge 15$. This is actually consistent with the large-$N$ theory, which predicts that the VBS state immediately follows the N\'eel state, because the expected spontaneous order is too weak to be detected., Comment: 5 pages, 5 figures

In recent years, high-performance piezoelectric micromachined ultrasonic transducers (PMUTs) have been fabricated by micro electro mechanical systems (MEMS) technology. For high-resolution imaging, it is important to broaden the frequency bandwidth. By reducing the diaphragm size to increase the resonance frequency, the film thickness becomes relatively larger and hence the transmitting and receiving characteristics may different from those of a usual thin diaphragm. In this study, we examine the performance of a square-diaphragm-type lead zirconate titanate (PZT) transducer through simulations. To realize the desired resonance frequency of 20 MHz, firstly, the diaphragm size and the thickness of the layers of PZT and Si constituting a PMUT are examined, and then, three PZT/Si models with different thicknesses are selected. Subsequently, using the models, we analyze the transmitting efficiency, transmitting bandwidth, receiving sensitivity (piezoelectric voltage/electric charge), and receiving bandwidth using an FEM simulator. It is found that the proposed models can transmit ultrasound independently of the diaphragm vibration and have wide bandwidth of the receiving frequency as compared with that of a typical PMUT.

We propose a scaling relation for critical phenomena in which a symmetry-breaking field is dengerously irrelevant. We confirm its validity on the 6-state clock model in three and four dimensions by numerical simulation. In doing so, we point out the problem in the previously-used order parameter, and present an alternative evidence based on the mass-dependent fluctuation., 5 pages, 5 figures

We report magnetization, specific heat, and NMR measurements of 3-Br-4-F-V [=3-(3-bromo-4-fluorophenyl)-1,5-diphenylverdazyl], a strong-rung S=1/2 Heisenberg spin ladder with ferromagnetic leg interactions. We explain the magnetic and thermodynamic properties based on the strong-rung regime. Furthermore, we find a field-induced successive phase transition in the specific heat and the nuclear spin-lattice relaxation rate 1/T1. 19F-NMR spectra for higher- and lower-temperature phases indicate partial magnetic order and incommensurate long-range order, respectively, evidencing the presence of frustration due to weak interladder couplings., 12 pages, 3 figures

A new type of magnetically frustrated lattice is found in the layered fluoride NaBa2Mn3F11. A kagome-type array of regular triangles composed of Mn2+ ions (spin 5/2) deforms so as to generate the next-nearest-neighbor interaction J2 between three out of six spins in the hexagon of a normal kagome lattice, in addition to the nearest-neighbor interaction J1. As a function of |J2/J1|, this lattice can interconnect the kagome (J2 = 0) and the triangular (J2 = J1) lattices and thus is called the kagome-triangular (KT) lattice. Magnetic susceptibility and heat capacity measurements performed on a polycrystalline sample of NaBa2Mn3F11 show an intensive short-range antiferromagnetic correlation below 14 K probably due to the specific magnetic frustration of the KT lattice. In addition, a long-range order at 2.0 K is observed, which is significantly low compared with the antiferromagnetic Weiss temperature of 32.3 K. Theoretical considerations of Heisenberg spins in the KT lattice reveal unique non-coplanar magnetic orders in the case of ferromagnetic J1 and antiferromagnetic J2. NaBa2Mn3F11 may actually exist in this regime according to the results of our analysis based on classical Monte-Carlo simulation., 5 figures