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    High-resolution bone microstructure imaging based on ultrasonic frequency-domain full-waveform inversion
    Yifang Li(李义方), Qinzhen Shi(石勤振), Ying Li(李颖), Xiaojun Song(宋小军), Chengcheng Liu(刘成成), Dean Ta(他得安), and Weiqi Wang(王威琪)
    Chin. Phys. B, 2021, 30 (1): 014302.   DOI: 10.1088/1674-1056/abc7aa
    Abstract125)      PDF (9210KB)(375)      
    The main challenge in bone ultrasound imaging is the large acoustic impedance contrast and sound velocity differences between the bone and surrounding soft tissue. It is difficult for conventional pulse-echo modalities to give accurate ultrasound images for irregular bone boundaries and microstructures using uniform sound velocity assumption rather than getting a prior knowledge of sound speed. To overcome these limitations, this paper proposed a frequency-domain full-waveform inversion (FDFWI) algorithm for bone quantitative imaging utilizing ultrasonic computed tomography (USCT). The forward model was calculated in the frequency domain by solving the full-wave equation. The inverse problem was solved iteratively from low to high discrete frequency components via minimizing a cost function between the modeled and measured data. A quasi-Newton method called the limited-memory Broyden-Fletcher-Goldfarb-Shanno algorithm (L-BFGS) was utilized in the optimization process. Then, bone images were obtained based on the estimation of the velocity and density. The performance of the proposed method was verified by numerical examples, from tubular bone phantom to single distal fibula model, and finally with a distal tibia-fibula pair model. Compared with the high-resolution peripheral quantitative computed tomography (HR-pQCT), the proposed FDFWI can also clearly and accurately presented the wavelength scaled pores and trabeculae in bone images. The results proved that the FDFWI is capable of reconstructing high-resolution ultrasound bone images with sub-millimeter resolution. The parametric bone images may have the potential for the diagnosis of bone disease.
    Doping effects of transition metals on the superconductivity of (Li,Fe)OHFeSe films
    Dong Li(李栋), Peipei Shen(沈沛沛), Sheng Ma(马晟), Zhongxu Wei(魏忠旭), Jie Yuan(袁洁), Kui Jin(金魁), Li Yu(俞理), Fang Zhou(周放), Xiaoli Dong(董晓莉), and Zhongxian Zhao(赵忠贤)
    Chin. Phys. B, 2021, 30 (1): 017402.   DOI: 10.1088/1674-1056/abd2ab
    Abstract75)      PDF (998KB)(64)      
    The doping effects of transition metals (TMs = Mn, Co, Ni, and Cu) on the superconducting critical parameters are investigated in the films of iron selenide (Li,Fe)OHFeSe. The samples are grown via a matrix-assisted hydrothermal epitaxy method. Among the TMs, the elements of Mn and Co adjacent to Fe are observed to be incorporated into the crystal lattice more easily. It is suggested that the doped TMs mainly occupy the iron sites of the intercalated (Li,Fe)OH layers rather than those of the superconducting FeSe layers. We find that the critical current density J c can be enhanced much more strongly by the Mn dopant than the other TMs, while the critical temperature T c is weakly affected by the TM doping.
    Electric gating of the multichannel conduction in LaAlO3/SrTiO3 superlattices
    Shao-Jin Qi(齐少锦), Xuan Sun(孙璇), Xi Yan(严曦), Hui Zhang(张慧), Hong-Rui Zhang(张洪瑞), Jin-E Zhang(张金娥), Hai-Lin Huang(黄海林), Fu-Rong Han(韩福荣), Jing-Hua Song(宋京华), Bao-Gen Shen(沈保根), and Yuan-Sha Chen(陈沅沙)
    Chin. Phys. B, 2021, 30 (1): 017301.   DOI: 10.1088/1674-1056/abc54c
    Abstract53)      PDF (874KB)(22)      
    The electric gating on the transport properties of two-dimensional electron gas (2DEG) at the interface of LaAlO3/SrTiO3 (LAO/STO) heterostructure has attracted great research interest due to its potential application in field-effect devices. Most of previous works of gate effect were focused on the LAO/STO heterostructure containing only one conductive interface. Here, we systematically investigated the gate effect on high-quality LAO/STO superlattices (SLs) fabricated on the TiO2-terminated (001) STO substrates. In addition to the good metallicity of all SLs, we found that there are two types of charge carriers, the majority carriers and the minority carriers, coexisting in the SLs. The sheet resistance of the SLs with a fixed thickness of the LAO layer increases monotonically as the thickness of the STO layer increases. This is derived from the dependence of the minority carrier density on the thickness of STO. Unlike the LAO/STO heterostructure in which minority and majority carriers are simultaneously modulated by the gate effect, the minority carriers in the SLs can be tuned more significantly by the electric gating while the density of majority carriers is almost invariable. Thus, we consider that the minority carriers may mainly exist in the first interface near the STO substrate that is more sensitive to the back-gate voltage, and the majority carriers exist in the post-deposited STO layers. The SL structure provides the space separation for the multichannel conduction in the 2DEG, which opens an avenue for the design of field-effect devices based on LAO/STO heterostructure.
    High temperature strain glass in Ti-Au and Ti-Pt based shape memory alloys
    Shuai Ren(任帅), Chang Liu(刘畅), and Wei-Hua Wang(汪卫华)
    Chin. Phys. B, 2021, 30 (1): 018101.   DOI: 10.1088/1674-1056/abc54a
    Abstract46)      PDF (902KB)(22)      
    Strain glass is a frozen short-range strain ordered state found in shape memory alloys recently, which exhibits novel properties around the ideal glass transition temperature T0. However, the T0 of current strain glass systems is still very low, limiting their potential applications and experimental studies. In this paper, we reported two new strain glass systems with relatively high T0. In Ti50Au50-xCrx alloys, the strain glass appears at x=25, and exhibits a T0 of 251 K, while in Ti50Pt50-yFey alloys, the strain glass takes place at y=30, and shows a T0 of 272 K. Both of them are comparable with the highest T0 value reported so far. Moreover, the phase diagrams of main strain glass systems in Ti-based alloys were summarized. It is found that the influence of the martensitic transformation temperature of the host alloy on the T0 of the strain glass is limited. This work may help to design new strain glass systems with higher T0 above ambient temperature.
    Edge-and strain-induced band bending in bilayer-monolayer Pb2Se3 heterostructures
    Peng Fan(范朋), Guojian Qian(钱国健), Dongfei Wang(王东飞), En Li(李恩), Qin Wang(汪琴), Hui Chen(陈辉), Xiao Lin(林晓), and Hong-Jun Gao(高鸿钧)
    Chin. Phys. B, 2021, 30 (1): 018105.   DOI: 10.1088/1674-1056/abcf92
    Abstract42)      PDF (1091KB)(19)      
    By using scanning tunneling microscope/microscopy (STM/STS), we reveal the detailed electronic structures around the sharp edges and strained terraces of lateral monolayer-bilayer Pd2Se3 heterostructures. We find that the edges of such heterostructures are well-defined zigzag type. Band bending and alignment are observed across the zigzag edge, forming a monolayer-bilayer heterojunction. In addition, an n-type band bending is induced by strain on a confined bilayer Pd2Se3 terrace. These results provide effective toolsets to tune the band structures in Pd2Se3-based heterostructures and devices.
    Structural and electrical transport properties of Cu-doped Fe1 -xCuxSe single crystals
    He Li(李贺), Ming-Wei Ma(马明伟), Shao-Bo Liu(刘少博), Fang Zhou(周放), and Xiao-Li Dong(董晓莉)
    Chin. Phys. B, 2020, 29 (12): 127404.   DOI: 10.1088/1674-1056/abc3af
    Abstract347)      PDF (859KB)(440)      
    We report the structural and electrical transport properties of Fe1 -xCuxSe (x = 0, 0.02, 0.05, 0.10) single crystals grown by a chemical vapor transport method. Substituting Cu for Fe suppresses both the nematicity and superconductivity of FeSe single crystal, and provokes a metal-insulator transition. Our Hall measurements show that the Cu substitution also changes an electron dominance at low temperature of un-doped FeSe to a hole dominance of Cu-doped Fe1 -xCuxSe at x = 0.02 and 0.1, and reduces the sign-change temperature (TR) of the Hall coefficient (R H).
    Realization of ultralow power phase locking by optimizing Q factor of resonant photodetector
    Jin-Rong Wang(王锦荣), Hong-Yu Zhang(张宏宇), Zi-Lin Zhao(赵子琳), and Yao-Hui Zheng(郑耀辉)
    Chin. Phys. B, 2020, 29 (12): 124207.   DOI: 10.1088/1674-1056/abbbfb
    Abstract162)      PDF (684KB)(209)      
    We design and construct a resonant photodetector (RPD) with a Q factor of 320.83 at the resonant frequency of 38.5 MHz on the basis of a theoretical analysis. Compared with the existing RPD under the same conditions, the signal-to-noise-ratio of the error signal is increased by 15 dB and the minimum operation power is reduced from -55 dBm to -70 dBm. By comparing the standard deviations of the stability curves, we confirm that the RPD has a dramatic improvement on ultralow power extraction. In virtue of the RPD, we have completed the demonstration of channel multiplexing quantum communication.
    Compact NbN resonators with high kinetic inductance
    Xing-Yu Wei(魏兴雨), Jia-Zheng Pan(潘佳政), Ya-Peng Lu(卢亚鹏), Jun-Liang Jiang(江俊良), Zi-Shuo Li(李子硕), Sheng Lu(卢盛), Xue-Cou Tu(涂学凑), Qing-Yuan Zhao(赵清源), Xiao-Qing Jia(贾小氢), Lin Kang(康琳), Jian Chen(陈健), Chun-Hai Cao(曹春海), Hua-Bing Wang(王华兵), Wei-Wei Xu(许伟伟), Guo-Zhu Sun(孙国柱), and Pei-Heng Wu(吴培亨)
    Chin. Phys. B, 2020, 29 (12): 128401.   DOI: 10.1088/1674-1056/abc2b8
    Abstract117)      PDF (932KB)(98)      
    We design and fabricate Λ/2 coplanar waveguide NbN resonators, the thickness and length of which are only several nanometers and hundred microns, respectively. The quality factor of such compact resonators can reach up to 7.5×104 at single photon power level at 30 mK with the resonance frequency around 6.835 GHz. In order to tune the resonant frequency, the resonator is terminated to the ground with a dc-SQUID. By tuning the magnetic flux in the dc-SQUID, the effective inductance of the dc-SQUID is varied, which leads to the change in the resonant frequency of the resonator. The tunability range is more than 30 MHz and the quality factor is about 3×103. These compact and tunable NbN resonators have potential applications in the quantum information processing, such as in the precision measurement, coupling and/or reading out the quantum states of qubits.
    Reliability of organic light-emitting diodes in low-temperature environment
    Saihu Pan(潘赛虎), Zhiqiang Zhu(朱志强), Kangping Liu(刘康平), Hang Yu(于航), Yingjie Liao(廖英杰), Bin Wei(魏斌), Redouane Borsali, and Kunping Guo(郭坤平)
    Chin. Phys. B, 2020, 29 (12): 128503.   DOI: 10.1088/1674-1056/abc154
    Abstract125)      PDF (685KB)(125)      
    Organic light-emitting diode (OLED) is an electroluminescent technology that relies on charge-carrier dynamics and is a potential light source for variable environmental conditions. Here, by exploiting a self-developed low-temperature testing system, we investigated the characteristics of hole/electron transport, electro-optic conversion efficiency, and operation lifetime of OLEDs at low-temperature ranging from -40 °C to 0 °C and room temperature (25 °C). Compared to devices operating at room temperature, the carrier transport capability is significantly decreased with reducing temperature, and especially the mobility of the hole-transporting material (HTM) and electron-transporting material (ETM) at -40 °C decreases from 1.16× 10-6 cm2/Vs and 2.60× 10-4 cm2/Vs to 6.91× 10-9 cm2/Vs and 1.44× 10-5 cm2/Vs, respectively. Indeed, the temperature affects differently on the mobilities of HTM and ETM, which favors unbalanced charge-carrier transport and recombination in OLEDs, thereby leading to the maximum current efficiency decreased from 6.46 cdA-1 at 25 °C to 2.74 cdA-1 at -40 °C. In addition, blue fluorescent OLED at -20 °C has an above 56% lifetime improvement (time to 80% of the initial luminance) over the reference device at room temperature, which is attributed to efficiently dissipating heat generated inside the device by the low-temperature environment.
    Peierls-phase-induced topological semimetals in an optical lattice: Moving of Dirac points, anisotropy of Dirac cones, and hidden symmetry protection
    Jing-Min Hou(侯净敏)
    Chin. Phys. B, 2020, 29 (12): 120305.   DOI: 10.1088/1674-1056/abc0de
    Abstract157)      PDF (1439KB)(160)      
    We propose a square optical lattice in which some of neighbor hoppings have a Peierls phase. The Peierls phase makes the lattice have a special band structure and induces the existence of Dirac points in the Brillouin zone, which means that topological semimetals exist in the system. The Dirac points move with the change of the Peierls phase and the Dirac cones are anisotropic for some vales of the Peierls phase. The lattice has a novel hidden symmetry, which is a composite antiunitary symmetry composed of a translation operation, a sublattice exchange, a complex conjugation, and a local U(1) gauge transformation. We prove that the Dirac points are protected by the hidden symmetry and perfectly explain the moving of Dirac points with the change of the Peierls phase based on the hidden symmetry protection.
    Collective modes of Weyl fermions with repulsive S-wave interaction
    Xun-Gao Wang(王勋高), Huan-Yu Wang(王寰宇), Jiang-Min Zhang(张江敏), Wu-Ming Liu(刘伍明)
    Chin. Phys. B, 2020, 29 (11): 117201.   DOI: 10.1088/1674-1056/abbbdb
    Abstract305)   HTML    PDF (731KB)(379)      

    We calculate the spin and density susceptibility of Weyl fermions with repulsive S-wave interaction in ultracold gases. Weyl fermions have a linear dispersion, which is qualitatively different from the parabolic dispersion of conventional materials. We find that there are different collective modes for the different strengths of repulsive interaction by solving the poles equations of the susceptibility in the random-phase approximation. In the long-wavelength limit, the sound velocity and the energy gaps vary with the different strengths of the interaction in the zero sound mode and the gapped modes, respectively. The particle–hole continuum is obtained as well, where the imaginary part of the susceptibility is nonzero.

    Surface states modulated exchange interaction in Bi2Se3/thulium iron garnet heterostructures
    Hai-Bin Shi(石海滨), Li-Qin Yan(闫丽琴), Yang-Tao Su(苏仰涛), Li Wang(王力), Xin-Yu Cao(曹昕宇), Lin-Zhu Bi(毕林竹), Yang Meng(孟洋), Yang Sun(孙阳), Hong-Wu Zhao(赵宏武)
    Chin. Phys. B, 2020, 29 (11): 117302.   DOI: 10.1088/1674-1056/abbbdf
    Abstract179)   HTML    PDF (773KB)(199)      

    We investigate the modulation of magnetic anisotropy of thulium iron garnet (TmIG) films by interfaced Bi2Se3 thin films. High quality epitaxial growth of Bi2Se3 films has been achieved by molecular beam epitaxy on TmIG films. By the method of ferromagnetic resonance, we find that the perpendicular magnetic anisotropy (PMA) of TmIG can be greatly strengthened by the adjacent Bi2Se3 layer. Moreover, the competition between topological surface states and thickness dependent bulk states of Bi2Se3 gives rise to the modulation of PMA of the Bi2Se3/TmIG heterostructures. The interfacial interaction can be attributed to the enhanced exchange coupling between Fe3+ ions of TmIG mediated by topological surface electrons of Bi2Se3.

    Thermal entanglement in a spin-1/2 Ising–Heisenberg butterfly-shaped chain with impurities
    Meng-Ru Ma(马梦如), Yi-Dan Zheng(郑一丹), Zhu Mao(毛竹), Bin Zhou(周斌)
    Chin. Phys. B, 2020, 29 (11): 110308.   DOI: 10.1088/1674-1056/abbbde
    Abstract152)   HTML    PDF (2706KB)(143)      

    We investigate the effect of impurities on the thermal entanglement in a spin-1/2 Ising–Heisenberg butterfly-shaped chain, where four interstitial Heisenberg spins are localized on the vertices of a rectangular plaquette in a unit block. By using the transfer-matrix approach, we numerically calculate the partition function and the reduced density matrix of this model. The bipartite thermal entanglement between different Heisenberg spin pairs is quantified by the concurrence. We also discuss the fluctuations caused by the impurities through the uniform distribution and the Gaussian distribution. Considering the effects of the external magnetic field, temperature, Heisenberg and Ising interactions as well as the parameter of anisotropy on the thermal entanglement, our results show that comparing with the case of the clean model, in both the two-impurity model and the impurity fluctuation model the entanglement is more robust within a certain range of anisotropic parameters and the region of the magnetic field where the entanglement occurred is also larger.

    Twisted and coiled bamboo artificial muscles for moisture responsive torsional and tensile actuation
    Xiaoyu Hu(胡晓宇), Xueqi Leng(冷雪琪), Tianjiao Jia(贾天娇), Zunfeng Liu(刘遵峰)
    Chin. Phys. B, 2020, 29 (11): 118103.   DOI: 10.1088/1674-1056/abbbda
    Abstract142)   HTML    PDF (1197KB)(151)      

    Smart textiles responding to the ambient environment like temperature, humidity, and light are highly desirable to improve the comfortability and realize multifunctions. The bamboo yarn has merits like air permeability, biodegradability, and excellent heat dissipation performance, but it has not been prepared for responsive materials and smart textiles. In this paper, the moisture-responsive twisted bamboo yarns were plied to form a self-balanced torsional actuator and wrapped around a mandrel to form a coil, followed by water immersion and evaporation to fix the shape and serve as a tensile actuator. A torsional actuation of 64.4°⋅ mm−1 was realized for the twisted actuator in 4.2 s; a maximum elongation of 133% or contraction of 50% was achieved for a coiled tensile actuator with good cyclability. The porous structure of bamboo yarns helped improve the water absorbance speed and decrease the response time of moisture. The self-balanced two-ply physical structure and reversible generation of chemical phase after soaking in aqueous solution fixed internal stress and provided good cyclability. With the unique properties including aqueous water-induced shape fixation and moisture-induced actuation, the application of tensile actuation of bamboo yarns was demonstrated, showing promising prospects on smart textiles.

    Near 100% spectral-purity photons from reconfigurable micro-rings
    Pingyu Zhu(朱枰谕), Yingwen Liu(刘英文), Chao Wu(吴超), Shichuan Xue(薛诗川), Xinyao Yu(于馨瑶), Qilin Zheng(郑骑林), Yang Wang(王洋), Xiaogang Qiang(强晓刚), Junjie Wu(吴俊杰), Ping Xu(徐平)
    Chin. Phys. B, 2020, 29 (11): 114201.   DOI: 10.1088/1674-1056/abbb28
    Abstract119)   HTML    PDF (910KB)(167)      

    We propose an on-chip reconfigurable micro-ring to engineer the spectral-purity of photons. The micro-ring resonator is designed to be coupled by one or two asymmetric Mach–Zehnder interferometers and the coupling coefficients hence the quality-factors of the pump and the converted photons can be dynamically changed by the interferometer’s internal phase-shifter. We calculate the joint-spectrum function and obtain the spectral-purity of photons and Schmidt number under different phases. We show that it is a dynamical method to adjust the spectral-purity and can optimize the spectral-purity of photons up to near 100%. The condition for high-spectral-purity photons is ensured by the micro-ring itself, so it overcomes the trade-off between spectral purity and brightness in the traditional post-filtering method. This scheme is robust to fabrication variations and can be successfully applied in different fabrication labs and different materials. Such high-spectral-purity photons will be beneficial for quantum information processing like Boson sampling and other quantum algorithms.

    Magnetization reorientation induced by spin–orbit torque in YIG/Pt bilayers
    Ying-Yi Tian(田颖异), Shuan-Hu Wang(王拴虎), Gang Li(李刚), Hao Li(李豪), Shu-Qin Li(李书琴), Yang Zhao(赵阳), Xiao-Min Cui(崔晓敏), Jian-Yuan Wang(王建元), Lv-Kuan Zou(邹吕宽), Ke-Xin Jin(金克新)
    Chin. Phys. B, 2020, 29 (11): 117504.   DOI: 10.1088/1674-1056/abb666
    Abstract130)   HTML    PDF (735KB)(98)      

    In this work, we report the reorientation of magnetization by spin–orbit torque (SOT) in YIG/Pt bilayers. The SOT is investigated by measuring the spin Hall magnetoresistance (SMR), which is highly sensitive to the direction of magnetic moment of YIG. An external in-plane rotating magnetic field which is applied to the YIG/Pt bilayers, and the evolutions of SMR under different injected currents in the Pt layer, result in deviation of SMR curve from the standard shape. We conclude that the SOT caused by spin accumulation near the interface between YIG and Pt can effectively reorient the in-plane magnetic moment of YIG. This discovery provides an effective way to modulate YIG magnetic moments by electrical methods.

    Room temperature nonlinear mass sensing based on a hybrid spin-nanoresonator system
    Jian-Yong Yang(杨建勇), Hua-Jun Chen(陈华俊)
    Chin. Phys. B, 2020, 29 (10): 107801.   DOI: 10.1088/1674-1056/abaee0
    Abstract153)   HTML    PDF (449KB)(132)      

    We present a room temperature nonlinear mass sensing based on a hybrid spin-nanoresonator system with the microwave pump–probe technique and the spin readout technique, which includes a single spin of nitrogen–vacancy (NV) center in diamond and a nanomechanical cantilever. The resonance frequency of the nanoresonator can be measured with the nolinear Kerr spectrum, and the parameters that influence the nolinear Kerr spectrum are also investigated. Further, according to the relationship between frequency shifts and variable mass attached on the nanoresonator, this system can also be used to detect the mass of DNA molecules with the nolinear Kerr spectrum. Benefiting from the single spin of the NV center in diamond has a long coherence time at 300 K, the hybrid system can realize room temperature mass sensor, and the mass response rate can reach 2600 zg/Hz.

    Two-step high-pressure high-temperature synthesis of nanodiamonds from naphthalene
    Tong Liu(刘童), Xi-Gui Yang(杨西贵), Zhen Li(李振), Yan-Wei Hu(胡宴伟), Chao-Fan Lv(吕超凡), Wen-Bo Zhao(赵文博), Jin-Hao Zang(臧金浩), Chong-Xin Shan(单崇新)
    Chin. Phys. B, 2020, 29 (10): 108102.   DOI: 10.1088/1674-1056/abad1c
    Abstract132)   HTML    PDF (892KB)(100)      

    Nanodiamonds have outstanding mechanical properties, chemical inertness, and biocompatibility, which give them potential in various applications. Current methods for preparing nanodiamonds often lead to products with impurities and uneven morphologies. We report a two-step high-pressure high-temperature (HPHT) method to synthesize nanodiamonds using naphthalene as the precursor without metal catalysts. The grain size of the diamonds decreases with increasing carbonization time (at constant pressure and temperature of 11.5 GPa and 700 °C, respectively). This is discussed in terms of the different crystallinities of the carbon intermediates. The probability of secondary anvil cracking during the HPHT process is also reduced. These results indicate that the two-step method is efficient for synthesizing nanodiamonds, and that it is applicable to other organic precursors.

    Evidence for bosonic mode coupling in electron dynamics of LiFeAs superconductor
    Cong Li(李聪), Guangyang Dai(代光阳), Yongqing Cai(蔡永青), Yang Wang(王阳), Xiancheng Wang(望贤成), Qiang Gao(高强), Guodong Liu(刘国东), Yuan Huang(黄元), Qingyan Wang(王庆艳), Fengfeng Zhang(张丰丰), Shenjin Zhang(张申金), Feng Yang(杨峰), Zhimin Wang(王志敏), Qinjun Peng(彭钦军), Zuyan Xu(许祖彦), Changqing Jin(靳常青), Lin Zhao(赵林), X J Zhou(周兴江)
    Chin. Phys. B, 2020, 29 (10): 107402.   DOI: 10.1088/1674-1056/abb21f
    Abstract221)   HTML    PDF (1392KB)(256)      

    Super-high resolution laser-based angle-resolved photoemission measurements are carried out on LiFeAs superconductor to investigate its electron dynamics. Three energy scales at ∼ 20 meV, ∼ 34 meV, and ∼ 55 meV are revealed for the first time in the electron self-energy both in the superconducting state and normal state. The ∼ 20 meV and ∼ 34 meV scales can be attributed to the coupling of electrons with sharp bosonic modes which are most likely phonons. These observations provide definitive evidence on the existence of mode coupling in iron-based superconductors.

    High performance RE–Fe–B sintered magnets with high-content misch metal by double main phase process
    Yan-Li Liu(刘艳丽), Qiang Ma(马强), Xin Wang(王鑫), Jian-Jun Zhou(周建军), Tong-Yun Zhao(赵同云), Feng-Xia Hu(胡凤霞), Ji-Rong Sun(孙继荣), Bao-Gen Shen(沈保根)
    Chin. Phys. B, 2020, 29 (10): 107504.   DOI: 10.1088/1674-1056/abb3f7
    Abstract69)   HTML    PDF (1821KB)(69)      

    Double main phase process is applied to fabricate [(Pr, Nd)1 – xMMx]13.8FebalM1.5B5.9 (x = 0.5 and 0.7; M = Cu, Al, Co, and Nb) sintered magnets with high misch metal (MM) content. In comparison to the magnets by single main phase process, the enhanced magnetic properties have been achieved. For magnets of x = 0.7, Hcj increases to 371.9 kA/m by 60.5%, and (BH)max is significantly enhanced to 253.3 kJ/m3 by 56.9%, compared with those of the single main phase magnets of the same nominal composition. In combination with minor loops and magnetic recoil curves, the property improvement of magnets with double main phase method is well explained. As a result, it is demonstrated that double main phase technology is an effective approach to improve the permanent magnetic properties of MM based sintered magnets.

ISSN 1674-1056   CN 11-5639/O4

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