We present a brief review focusing on recent research progress in high-field electron spin resonance (ESR) spectrometer with a focus on the construction and application of a 25-Tesla high-field ESR system. The spectrometer is based on a water-cooled resistive magnet at the Steady High Magnetic Field Facility in Hefei, China. Sample temperatures can be regulated between 2 to 300K using a 4He variable-temperature insert cryostat. A broadband microwave source, covering a frequency range of 50 to 690GHz is achieved through a series of multiplier chain amplifiers, and signal detection is performed using an InSb bolometer. Key components of the spectrometer, including the probe, waveguide, and LabVIEW-based data acquisition software, are also described. The system’s performance was evaluated using the standard sample 2,2-diphenyl-1-picrlyhydrazyl. The spectrometer was primarily designed to support external users in investigating spin systems under extreme conditions—such as observing antiferromagnetic resonance in spin-ordered phases or detecting resonance signals in systems with large zero-field splitting, which are typically inaccessible to conventional X-band spectrometers. To illustrate its applicability, representative examples from materials science and condensed matter physics are provided.

Kitaev interactions, arising from the interplay of frustration and bond anisotropy, can lead to strong quantum fluctuations and, in an ideal case, to a quantum-spin-liquid state. However, in many nonideal materials, spurious non-Kitaev interactions typically promote a zigzag antiferromagnetic order in the d-orbital transition metal compounds. By combining neutron scattering with muon-spin rotation and relaxation techniques, we provide new insights into the exotic properties of Na2Co2TeO6, a candidate Kitaev material. Below TN, the zero-field muon-spin relaxation rate becomes almost constant (at 0.45 us-1). We attribute this temperature-independent muon-spin relaxation rate to the strong quantum fluctuations, as well as to the frustrated Kitaev interactions. As the magnetic field increases, neutron scattering data indicate a much broader spin-wave-excitation gap at the K-point. Therefore, quantum fluctuations seem not only robust, but are even enhanced by the applied magnetic field. Our findings provide valuable hints for understanding the onset of the quantum-spin-liquid state in Kitaev materials.

Spinel compounds are of great interest in both fundamental and application-oriented perspectives due to the geometric magnetic frustration inherent to their lattice and the resulting complex magnetic states. Here, we applied x-ray diffraction, magnetization, heat capacity and powder inelastic neutron scattering measurements, along with theoretical calculations, to study the exotic properties of chromite-spinel oxides CoCr2O4 and MnCr2O4. The temperature dependence of the phonon spectra provides an insight into the correlation between oxygen motion and the magnetic order, as well as the magnetoelectric effect in the ground state of MnCr2O4. Moreover, spin-wave excitations in CoCr2O4 and MnCr2O4 are compared with Heisenberg model calculations. This approach enables the precise determination of exchange energies and offers a comprehensive understanding of the spin dynamics and relevant exchange interactions in complicated spiral spin ordering.

Stacking two-dimensional (2D) van der Waals (vdW) materials in a layered bulk structure provides an appealing platform for the emergence of exotic physical properties. As a vdW crystal with exceptional plasticity, InSe offers the opportunity to explore various effects arising from the coupling of its peculiar mechanical behaviors and other physical properties. Here, we employ neutron scattering techniques to investigate the correlations of plastic interlayer slip, lattice anharmonicity, and thermal transport in InSe crystals. Not only are the interlayer slip direction and magnitude well captured by shifts in the Bragg reflections, but we also observe a deviation from the expected Debye behaviour in the heat capacity and lattice thermal conductivity. Combining the experimental data with first-principles calculations, we tentatively attribute the observed evidence of strong phonon-phonon interactions to a combination of a large acoustic-optical frequency resonance and a nesting effect. These findings correlate the macroscopic plastic slip and the microscopic lattice dynamics, providing insights into the mechano-thermo coupling and modulation in 2D vdW materials.

We study the ground state and spin excitations in Ba3MnSb2O9, an easy-plane S = 5/2 triangular lattice antiferromagnet. By combining single-crystal neutron scattering, electric spin resonance (ESR), and spin wave calculations, we determine the frustrated quasi-two-dimensional spin Hamiltonian parameters describing the material. While the material has a slight monoclinic structural distortion, which could allow for isoscelestriangular exchanges and biaxial anisotropy by symmetry, we observe no deviation from the behavior expected for spin waves in the in-plane 120 degrees state. Even the easy-plane anisotropy is so small that it can only be detected by ESR in our study. In conjunction with the quasitwo dimensionality, our study establishes that Ba3MnSb2O9 is a nearly ideal triangular lattice antiferromagnet with the quasiclassical spin S = 5/2, which suggests that it has the potential for an experimental study of Z- or Z2-vortex excitations.

Magnetic refrigeration around the liquid-helium temperature plays a critical role in many technological sectors. Even if gallium gadolinium garnet (GGG) has been regarded as the benchmark, its application is highly limited by the small magnetic entropy changes, the requirement of superconducting magnets, and the large device sizes. Here, we report that LiREF 4 (RE = rare earth) single crystals exhibit significantly superior magnetocaloric performance levels to commercial GGG. Under a small magnetic field of 5 kOe, which can be easily achieved by a permanent magnet, the magnetic entropy change reaches a record-high value of 16.7 J kg −1 K −1 in LiHoF 4 in contrast to the value of 1.0 J kg −1 K −1 in GGG. The combination of small driving fields, large entropy changes, and excellent thermal and/or magnetic reversibility enables this series to be employed as the ideal working material for compact magnetic refrigeration around the liquid-helium temperature.

We study the ground state and spin excitations in Ba3MnSb2O9, an easy-plane S = 5/2 triangular lattice antiferromagnet. By combining single-crystal neutron scattering, electric spin resonance (ESR), and spin wave calculations, we determine the frustrated quasi-two-dimensional spin Hamiltonian parameters describing the material. While the material has a slight monoclinic structural distortion, which could allow for isosceles-triangular exchanges and biaxial anisotropy by symmetry, we observe no deviation from the behavior expected for spin waves in the in-plane 120o state. Even the easy-plane anisotropy is so small that it can only be detected by ESR in our study. In conjunction with the quasi-two-dimensionality, our study establishes that Ba3MnSb2O9 is a nearly ideal triangular lattice antiferromagnet with the quasi-classical spin S = 5/2, which suggests that it has the potential for an experimental study of Z- or Z2-vortex excitations.

The orbital effect on the anomalous magnetism and evolution of low La-doping single crystals, La$_x$Y$_{1-x}$VO$_{3}$ (x = 0, 0.1, and 0.2), has been investigated by applying the X-ray diffraction, specific heat, magnetization and Raman scattering techniques. The larger nearest-neighbor (NN) exchange interaction along c-axis stabilizes the fluctuant G-type orbital ordering (G-OO) which favors the exotic C-type antiferromagnetic order (C-AF). It is found that the NN exchange interaction in ab plane is anisotropy relating to the in plane magnetic anisotropy, which becomes smaller in high La-doped sample. Most interestingly, with increasing the La$^{3+}$ content the orbital fluctuation and hybridization are decreased which stabilizes the C-OO phase and destabilizes the G-OO phase. Meanwhile, the diamagnetism in the exotic C-AF phase becomes weak and the possible mechanism relates to the change of the competition between the single-ion magnetic anisotropy and the Dzyaloshinsky-Moriya (DM) interaction with increasing x. Finally, the strong spin-orbital coupling has been observed at temperature just above T$_N$ in La$_{0.2}$Y$_{0.8}$VO$_{3}$ and a short range spin-orbital correlation is suggested.

High-entropy ceramics (HECs) are solid solutions of inorganic compounds with one or more Wyckoff sites shared by equal or near-equal atomic ratios of multi-principal elements. Material design and property tailoring possibilities emerge from this new class of materials. Here, we report the discovery of superconductivity around 2.35 K and topological properties in the (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C high-entropy carbide ceramic (HECC), which has not been observed before in any of the investigated HECC. Density functional theory calculations showed that six type-II Dirac points exist in (Ti0.2Zr0.2Nb0.2Hf0.2Ta0.2)C, which mainly contributed from the t2g orbitals of transition metals and the p orbitals of C. Due to the stability of the structure, we also observed robust superconductivity under pressure in this HEC superconductor. This study expands the physical properties of HECs, which may become a new material platform for superconductivity research, especially for studying the coupling between superconductivity and topological physics.

Spin liquids are exotic materials where the magnetic order is absent due to fluctuations at any finite temperature less than the spin interaction. Their occurrence is attributed to a high degree of ground state degeneracy. Wannier showed in 1950 that such a large degeneracy of ground state can theoretically take place in a two-dimensional (2D) triangular lattice with Ising spins, a classically geometrical frustrated lattice mode. So far, the geometrically frustrated lattice has a large family of systems: edge-shared triangles as a triangular lattice and corner-shared triangles as a kagomé lattice in a 2D system and corner-sharing tetrahedra as a pyrochlore lattice in a three-dimensional system, etc.

Two-dimensional (2D) Cr (1+ δ ) Te 2 materials exhibit strong magnetic ordering and high Curie temperatures, making them attractive for various applications. It is crucial to achieve controllable synthesis for their successful integration into device technologies. In this study, we present the synthesis of phase-controllable 2D Cr (1+ δ ) Te 2 films on the Si (111) substrate via molecular beam epitaxy. The composition and phase transition of the as-grown Cr (1+ δ ) Te 2 films are characterized by using in-situ reflection high-energy electron diffraction, scanning tunneling microscopy, ex-situ X-ray photoelectron spectroscopy, X-ray diffraction, and theoretical calculations. At low growth temperatures, by carefully adjusting the film thickness from 2 to more than 3 layers, we achieve precise control over the phase of Cr (1+ δ ) Te 2 , from CrTe 2 to Cr intercalated Cr 2 Te 3 . At a relatively elevated growth temperature, it is demonstrated that the Cr (1+ δ ) Te 2 phase is independent of the film thickness, only Cr 2 Te 3 forms and its growth mode is thickness-dependent. These phase transitions at low growth temperatures and growth mode changes at elevated growth temperatures are attributed to interfacial effects and the phase stability of Cr (1+ δ ) Te 2 compounds. Additionally, we utilize scanning tunneling spectroscopy and computations to gain insights into the electronic properties of Cr 2 Te 3 . The magnetic measurements reveal that the 30-nm Cr 2 Te 3 film exhibits ferromagnetic behavior with a Curie temperature of about 180 K. Our work offers a robust method for the controllable growth of high-quality 2D Cr (1+ δ ) Te 2 films on Si substrates, providing an ideal platform for investigating their intrinsic properties and advancing the development of 2D magnet-based spintronics devices.

One of the most important issues in modern condensed matter physics is the realization of fractionalized excitations, such as the Majorana excitations in the Kitaev quantum spin liquid. To this aim, the 3d-based Kitaev material Na2Co2TeO6 is a promising candidate whose magnetic phase diagram of B // a* contains a field-induced intermediate magnetically disordered phase within 7.5 T < |B| < 10 T. The experimental observations, including the restoration of the crystalline point group symmetry in the angle-dependent torque and the coexisting magnon excitations and spinon-continuum in the inelastic neutron scattering spectrum, provide strong evidence that this disordered phase is a field induced quantum spin liquid with partially polarized spins. Our variational Monte Carlo simulation with the effective K-J1-��-��'-J3 model reproduces the experimental data and further supports this conclusion.

As the simplest example of geometrical frustration, the two-dimensional triangular lattice antiferromagnet exhibits the mismatch between the lattice geometry and spin-exchange interaction, which has been the subject of intensive studies due to its exotic quantum phenomena. Here, we performed detailed studies of the magnetic structures and spin wave excitations by neutron powder diffraction and inelastic neutron scattering measurements on the triple-perovskite oxides Ba3MNb2O9 (M = Co, Ni, and Mn) with triangular-lattice geometry. The interplay between the frustrated interaction and easy-plane/axis anisotropy gives rise to two magnetic phase transition temperatures for Ba3MNb2O9 (Ba3MNb2O9 ) and only one for Ba3MNb2O9 . The linear spin-wave theory +1/S calculations indicate that both spatial dimensionality and the spin size have a significant impact on the strength of quantum fluctuations, which lead to their different magnetic ground states and exotic physical properties. Moreover, the effects of the thermal fluctuations are presented for Ba3MNb2O9 .

Objective: To evaluate the postoperative quality of life in patients after totally laparoscopic total gastrectomy (TLTG). Methods: A retrospective cohort study based on propensity score matching was performed. Clinical and follow-up data of patients who underwent laparoscopic radical gastrectomy at Union Hospital of Fujian Medical University from January 2014 to May 2015 were collected. Case indusion criteria: (1) primary gastric cancer confirmed by postoperative pathology; (2) receiving TLTG or laparoscopic-assisted total gastrectomy (LATG);(3) R0 resection; (4) completing follow-up for 12 months and complete follow-up data. Exclusion criteria: (1) gastric stump cancer; (2) concurrent tumor; (3) distal metastasis found during operation; (4) history of upper abdominal operation. According to surgical procedures, patients were divided into the LATG group (1076 cases) and the TLTG group (106 cases). To eliminate potential bias in baseline data between the two groups, the propensity score was calculated using a logistic regression model with the following covariates, including age, sex, body mass index, American Society of Anesthesiologists score, tumor location, tumor size, pathology type, and stage. The two groups were matched using a 1:2 propensity assessment ratio and a caliper width of 0.01 standard deviation was specified. The primary outcomes were the quality of life of the two groups at 3, 6 and 12 months after gastrectomy, including physical symptoms and social function. Higher function score indicated better function, and higher symptom score presented worse symptoms. Quality of life score = (100 - somatic symptom scale score + social function scale score) / 2. The secondary outcomes were postoperative nutritional recovery and food tolerance at 3, 6 and 12 months after gastrectomy. The categorical variables were expressed as n(%), and compared using the χ2 test or Fisher exact test. The continuous variables conforming to the normal distribution were represented by Mean ± SD and compared with the paired t-test. Repeated measurement of variance was used to compare nutrition-related indicators within the group among pre-operation, postoperative 1, 3, 6, 12 months. Results: After PSM, there were no significant differences in clinicopathological baseline data between the TLTG group (n=104) and the LATG group (n=208) (all P>0.05). The physical symptoms scores in the TLTG group before operation and 3, 6 and 12 months after operation were 8.6±5.8, 15.5±8.4, 10.1±5.9 and 6.1±2.4 respectively (F=43.493, P<0.001). In the LATG group, the above mentioned scores were 9.7±6.9, 23.7±10.4, 13.3±8.3 and 8.5±4.2 respectively (F=112.588, P<0.001). Compared with the LATG group, the symptom scores in the TLTG group were lower at 3 and 6 months after operation, and the differences were statistically significant (t=-3.653, P<0.001; t=-2.513, P=0.012). At 12 months after operation, although the physical symptom score in the TLTG group was also lower than that in LATG group, the difference was not statistically significant (t=-1.487, P=0.138). The social function scores in the TLTG group before operation and 3, 6 and 12 months after operation were 90.3±8.9, 77.5±14.3, 87.4±10.3 and 91.7±6.7 respectively (F=28.524, P<0.001). In the LATG group, the above mentioned scores were 92.5±6.3, 68.5±16.8, 79.8±14.7 and 84.7±11.1 respectively (F=57.975, P<0.001). Compared with the LATG group, the social function scores of patients in the LATG group were higher at 3, 6 and 12 months after operation (t=3.543, P<0.001; t=3.216, P=0.001; t=2.235, P=0.026). The total scores of quality of life at 3, 6 and 12 months after operation in the TLTG group were 81.0±15.6, 88.3±8.1 and 93.3±9.1 respectively, and the above mentioned scores in the LATG group were 72.4±13.6, 83.3±11.5 and 88.1±7.7 respectively, whose differences at corresponding time point were all significant between the two groups (all P<0.05). The change of total body mass[(-8.4±1.4)% vs. (-13.2±1.6)%, t=2.273, P=0.024], serum albumin[(-5.1±0.7)% vs. (-7.4±0.8)%,t=2.095, P=0.037], meal quantity [(-15.6±4.7)% vs. (-24.1±6.0)%, t=2.885, P=0.004] and meal times [(20.8±7.1)% vs. (30.6±11.5)%, t=3.043, P<0.001] in the TLTG group were significantly lower than those in the LATG group one year after operation (all P<0.05). At 3, 6 and 12 months after operation, the diet proportions of solid and soft food in the TLTG group were higher than those in the LATG group (all P<0.05). Conclusions: Compared with LATG, patients with gastric cancer undergoing TLTG have better health-related quality of life and faster recovery of nutrition.

The crystal structure of solid-state materials with unique lattices is considered one of the main factors determining physical properties, including superconductivity. Materials with honeycomb lattices have inspired intense research interest for their novel properties. A previously unknown compound, Ta4CoSi, are discussed herein and its crystal structure and superconducting properties. It crystallizes in a CuAl2-type structure (space group P4/mcm, No. 124) with the lattice parameters a = b = 6.17755(7){\AA} and c = 4.98443(8) {\AA}, featuring honeycomb networks of Ta-Ta in (110) plane. Superconductivity is observed below the critical temperature of 2.45 K, while lower and upper critical magnetic fields are 9.86 mT and 0.84 T, respectively. Experiments and theoretical calculations show that the honeycomb lattices significantly influence the superconducting properties. This material may thus provide a new platform for investigating the exotic superconductivity of honeycomb networks.

Objective: To examine the long term outcome of splenic hilar lymphadenectomy (SHL) for locally advanced Siewert type Ⅱ and Ⅲ adenocarcinoma of esophagogastric junction (AEG) with a tumor diameter ≥4 cm. Methods: A total of 489 locally advanced Siewert type Ⅱ and Ⅲ AEG patients with a tumor diameter ≥4 cm who underwent radical resection from January 2010 to April 2016 were included. There were 383 males and 106 females. There were 225 patients aged≥65 years and 264 patients aged <65 years. SHL was conducted in 270 patients(SHL group). Wilcoxon rank-sum test or χ2 test were conducted for inter-group comparison. Cox proportional hazard regression was used to analyze the long term outcome of SHL and the prognosis factors of overall survival. Kaplan-Meier curve was drawn finally. The results of survival analysis were verified by Log-rank test. Results: Followed-up to April 2021,the median follow-up time was 78.0 months (range: 74.0 to 85.0 months), the follow-up rate was 95.5%(467/489). The splenic hilar lymphnode metastasis rate of the SHL group was 12.6% (34/270). Younger patients (<65 years old), less complications, higher proportion of patients received adjuvant chemotherapy were demonstrated in the SHL group (χ2: 5.644 to 6.744, all P<0.05). Multivariate analysis showed that SHL was the independent prognosis factor of overall survival for patients with Siewert type Ⅱ and Ⅲ AEG and a tumor diameter≥4 cm (HR=0.68, 95%CI: 0.52 to 0.88, P=0.004) along with preoperative CA19-9, pathological T stage, pathological N stage, adjuvant chemotherapy and postoperative complication. Further subgroup analysis demonstrated that the SHL group had better 5-year overall survival than non-SHL group (62.4% vs. 39.2%, χ2=17.983, P=0.006) in Siewert type Ⅲ AEG rather than in Siewert type Ⅱ AEG(57.3% vs. 53.7%, χ2=3.031, P=0.805). Conclusion: In experienced center, splenic hilar lymphadenectomy can improve the prognosis of Siewert type Ⅲ AEG with a tumor diameter ≥4 cm.

The crystal structure of solid-state materials with unique lattices is considered one of the main factors determining physical properties, including superconductivity. Materials with honeycomb lattices have inspired intense research interest for their novel properties. A previously unknown compound, Ta4CoSi, are discussed herein and its crystal structure and superconducting properties. It crystallizes in a CuAl2-type structure (space group P4/mcm, No. 124) with the lattice parameters a = b = 6.17755(7){\AA} and c = 4.98443(8) {\AA}, featuring honeycomb networks of Ta-Ta in (110) plane. Superconductivity is observed below the critical temperature of 2.45 K, while lower and upper critical magnetic fields are 9.86 mT and 0.84 T, respectively. Experiments and theoretical calculations show that the honeycomb lattices significantly influence the superconducting properties. This material may thus provide a new platform for investigating the exotic superconductivity of honeycomb networks.

Kitaev physics has recently attracted attention in condensed matter for its anticipated quantum spin liquid (QSL) state. The thermal transport measurement is crucial for probing the features of charge-neutral quasiparticles. In this letter, we report a significant thermal Hall effect in Na2Co2TeO6 (NCTO), a Kitaev QSL candidate, when the magnetic field is applied along the out-of-plane direction of the honeycomb plane. The thermal conductivity (Kxx) and thermal Hall conductivity (Kxy) in NCTO reveal distinct magnetic field dependences below and above the Neel temperature (TN) of 27 K. For T > TN, Kxx has a monotonic decrease in the field dependence, while Kxy persists up to T ??? = 150 K. On the other hand, both Kxx and Kxy exhibit complex field dependence for

The neutron powder diffraction, specific heat, thermal conductivity, and Raman scattering measurements were presented to study the interplays of lattice, phonons and electrons of the Sr-doping Ba1-xSrxSnO3 (x was less than or equal to 0.1). Although Ba1-xSrxSnO3 kept the cubic lattice, the Raman spectra suggested a dynamic distortion at low temperature. The density functional theory was applied to analyze the electronic structures and phonon dispersions of Ba1-xSrxSnO3(x = 0, 0.0125), and the behaviors of electron bands around Fermi levels were discussed. According to the experimental and theoretical results, the Sr-doping played a significant role in tuning the indirect band gap of BaSnO3 and influenced the electron-phonon interaction.

The structure and magnetic properties of Mn1+xV2-xO4 (0 a) phase transition was observed. For x > 0.3, the system maintained the tetragonal lattice. The collinear and noncollinear magnetic transition was also observed for all compositions. To reveal the dynamics of the ground state, first principle simulation was applied to not only analyze the orbital effects of Mn2+, Mn3+, and V3+ ions, but also the related exchange energies.