Journal of Magnetism and Magnetic Materials最新文献

{"title":"Effect of magnetic and vibrational aging on residual stresses in ferromagnetic and nonferromagnetic materials","authors":"Zhiying Gao ,&nbsp;Hechuan Song ,&nbsp;Qingdong Zhang ,&nbsp;Boyang Zhang","doi":"10.1016/j.jmmm.2025.173436","DOIUrl":"10.1016/j.jmmm.2025.173436","url":null,"abstract":"<div><div>Magnetic stress relief (MSR) and vibration stress relief (VSR) were widely used in industry for their adaptability, efficiency, energy savings, and environmental benefits, and have been extensively studied. However, few studies focus on comparing the control of residual stress relief between MSR and VSR. In this paper, the effects of MSR at different magnetic field strengths and VSR at different vibration frequencies on the relief of residual stresses in ferromagnetic and nonferromagnetic materials were investigated experimentally, respectively. The results indicate that MSR can significantly reduce residual stress in ferromagnetic materials, with an average reduction of 19.07 %. The reduction exhibits a certain linear correlation with magnetic field strength. However, the relief effect on non-ferromagnetic materials is relatively minor, with a reduction of 8.92 %. VSR proves effective in relieving residual stress across both material types, with an average reduction of 20.98 % in ferromagnetic materials and up to 23.44 % in the width direction for non-ferromagnetic materials. The essence of VSR is the periodic application of an external excitation force. Plastic deformation occurs due to the combination of the excitation force and the internal residual stress of the material. Consequently, the yield limit of the material was improved, and its susceptibility to deformation was reduced. MSR primarily utilizes the magneto-induced vibration effect to relieve residual stress. For non-ferromagnetic materials, plastic deformation is mainly enhanced through dislocation relaxation. Both methods fundamentally involve the combination of external stress fields and the material’s residual stress, which forces dislocations to overcome resistance and migrate, thereby reducing residual stress. This study provides theoretical support and experimental basis for the development of a combined MSR and VSR method for residual stress relief.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173436"},"PeriodicalIF":3.0,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144867129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Residual magnetic scanning measurement for visualization evaluation on different damage stages of remanufactured blanks","authors":"Zhengchun Qian ,&nbsp;Yawen Dong ,&nbsp;Wei Wang ,&nbsp;Ruichen Zong ,&nbsp;Ninghui Li ,&nbsp;Yi Chen ,&nbsp;Huanbo Cheng ,&nbsp;Mengdi Gao ,&nbsp;Wenzheng Ding","doi":"10.1016/j.jmmm.2025.173435","DOIUrl":"10.1016/j.jmmm.2025.173435","url":null,"abstract":"<div><div>Different degrees of damage to ferromagnetic materials can be induced under external loading, which affects the service properties of components. The service life of these materials can be extended via remanufacturing. Nondestructive testing (NDT) of scrapped blanks is a critical step in remanufacturing, because it directly affects the quality of subsequent restoration processes. The traditional residual magnetic field (RMF) detection method, which relies primarily on magnetic signals obtained from one-dimensional (1-D) scanning lines for damage analysis, is prone to missed detection or false detection issues. Therefore, two-dimensional (2-D) residual magnetic scanning measurement (RMSM) technology is proposed in this paper to visualize the RMF distributions of the <em>H</em>_p(<em>x</em>), <em>H</em>_p(<em>y</em>), and <em>H</em>_p(<em>z</em>) components at different damage stages of ferromagnetic materials. The results show that the 2-D RMF distribution pattern of the <em>H</em>_p(<em>x</em>) component is highly consistent with the strain field measured by the digital image correlation (DIC) method. The <em>H</em>_p(<em>x</em>) magnetic field intensity has a linear fitting relationship with the strain. The 2-D RMF of the <em>H</em>_p(<em>y</em>) component can accurately invert the change process of the defect size under loading, and the 2-D RMF of the <em>H</em>_p(<em>z</em>) component visually shows the outline and the degree of necked of the samples. In addition, an automotive connecting rod remanufactured blank is selected to validate the feasibility of 2-D RMSM technology. These findings reveal that the stress concentration and crack damage can be effectively identified by 2-D RMSM, and its evaluation accuracy is greater than that of the traditional 1-D RMF.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173435"},"PeriodicalIF":3.0,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144858376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An improved J-A model for iron-based soft magnetic composites considering local demagnetization effect","authors":"Zhang Changgeng ,&nbsp;Guo Ziran ,&nbsp;Lin Zhiwei ,&nbsp;Li Yongjian","doi":"10.1016/j.jmmm.2025.173439","DOIUrl":"10.1016/j.jmmm.2025.173439","url":null,"abstract":"<div><div>Soft magnetic composites (SMCs), as three-dimensional (3D) isotropic materials can serve as substitutes for traditional laminated soft magnetic materials especially in 3D magnetic circuit devices such as claw-pole motors and power electronics. To utilize and optimize the properties of iron-based SMCs, it is essential to accurately model their magnetic properties at low frequencies and near saturation magnetic flux density. This paper proposes an improved J-A (Jiles-Atherton) model that predicts magnetization in SMCs by considering the influence of internal demagnetization on domain wall motion, incorporating an effective demagnetization factor to adjust the effective field. Simultaneously, a dynamic hysteresis model applicable to SMCs is established for the inter-particle and intra-particle eddy current losses of SMCs. Two iron-based SMC samples with 5 wt% and 7.5 wt% Ni-Zn ferrite content were fabricated via spark plasma sintering (SPS) and tested under static and dynamic magnetization of in-service conditions. A comparative analysis of experiments and simulations shows that the improved model accurately predicts hysteresis loops and iron losses, with relative errors under 8 % in the 10–100 Hz frequency range, which improvements are especially noticeable at the near saturable area of the simulation loop.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173439"},"PeriodicalIF":3.0,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of modes in magnetic tunnel junctions under various field orientations","authors":"Mariia D. Lobkova ,&nbsp;Georgy A. Kichin ,&nbsp;Petr N. Skirdkov ,&nbsp;Konstantin A. Zvezdin","doi":"10.1016/j.jmmm.2025.173425","DOIUrl":"10.1016/j.jmmm.2025.173425","url":null,"abstract":"<div><div>Magnetic tunnel junctions (MTJs) offer significant potential for next-generation spintronic devices operating in the microwave regime. An important feature of MTJs is their ability to rectify signals in the GHz frequency range. To further improve their microwave performance, it is critical to investigate how the orientation of the external magnetic field affects the magnetization dynamics. We perform an experimental and micromagnetic study to analyze how the direction and magnitude of the in-plane magnetic field affect the behavior of free-layer modes in a 100 nm diameter MTJ. We experimentally found a bulk mode and an edge mode in the free layer. By varying the in-plane field orientation, we identify regions with improved rectification by 50 degrees, control their width, and demonstrate how they can be frequency shifted. We also use an analytical model and micromagnetic simulations to analyze the nature and behavior of the observed modes.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173425"},"PeriodicalIF":3.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144809994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, magnetic and magnetocaloric properties of rare-earth based TbGd(MoO4)3 molybdates","authors":"Athira P ,&nbsp;Debasmita Bala ,&nbsp;Abhijit Nayak ,&nbsp;Devajyoti Mukherjee ,&nbsp;Jyothinagaram Krishnamurthy","doi":"10.1016/j.jmmm.2025.173434","DOIUrl":"10.1016/j.jmmm.2025.173434","url":null,"abstract":"<div><div>Rare-earth molybdates have drawn tremendous attention due to their magnetoelectric nature, including type-II multiferroicity and structural phase transitions linked to displacive type ferroelectricity, making them well-suited for multicaloric effect in solid-state refrigeration phenomena. This study focuses on the synthesis and crystal structure analysis, temperature and field- dependent magnetic susceptibility, and magnetocaloric properties of TbGd(MoO₄)₃ (TGMO) polycrystals. The magnetic field and temperature variation of magnetization and specific heat capacity were conducted to evaluate the spin contributed magnetic entropy changes (−Δ<em>S</em>_M) and temperature change under adiabatic (Δ<em>T</em>_ad) conditions in the synthesised sample. The investigated compound exhibits no obvious long-range order with in the measured low-temperature limit. The calculated –Δ<em>S</em>_M shows a maximum value of 13.6 Jkg⁻¹K⁻¹ at 3.5 K for 70 kOe. Moreover, the estimated temperature change under adiabatic conditions for TGMO was found to be 8.5 K. These characteristics, including a significant magnetocaloric effect with magnetic field and the absence of thermal and magnetic hysteresis loss, is comparable to good magnetic refrigerants near liquid helium temperatures.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173434"},"PeriodicalIF":3.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic, electrical and induction heating properties of magnetite/hematite mixed phase nanoparticles","authors":"Amrutha R. Menon,&nbsp;Niroj Kumar Sahu","doi":"10.1016/j.jmmm.2025.173432","DOIUrl":"10.1016/j.jmmm.2025.173432","url":null,"abstract":"<div><div>Iron oxides in nanoform are associated with exciting properties for various applications such as energy storage, magnetic recording, biomedicine and sensing. These applications demand the tuning of the physico-chemical properties of iron oxide especially Fe₃O₄ phase. However, iron oxides generally exist in mixed phases of any of its mostly occurred three phases magnetite, maghemite and hematite. Here, we report a solvothermally processed mixed phase of magnetite and hematite nanoparticles (NPs) which has been prepared using P123 triblock copolymer in addition to urea and hexamethylenetetramine (HMTA). The magnetite phase crystallizes in inverse spinel structure of Fe₃O₄ whereas hematite (α-Fe₂O₃) phase crystallizes in corundum structure. The use of copolymer leads to flake-shaped morphology of nanoparticles whereas use of urea and HMTA in different ratio gives different proportion of magnetite and hematite. The mixed iron oxide nanoparticles (IONPs) possess significantly different magnetic, electrical and dielectric properties than their bulk analogue. The surface analysis confirms the presence of magnetite and hematite phase in all the samples attributed to the coexistence of Fe³⁺ and Fe²⁺ ions. FESEM micrographs shows evenly distributed nanoparticles but in aggregated form. Furthermore, due to their weakly ferromagnetic behaviour with magnetisation value of ∼55 emu/g at 1.5 kOe field, the nanoparticles exhibited good induction heating behaviour under AC magnetic field. As high as 472 W/g of specific absorption rate was attained at a nanoparticle concentration of 1 mg/mL in water.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173432"},"PeriodicalIF":3.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144861170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Challenges and strategies in modeling and control of magnetic gears: A review","authors":"Abdelileh Mabrouk ,&nbsp;Olfa Ksentini ,&nbsp;Mohamed slim Abbes ,&nbsp;Mohamed Haddar","doi":"10.1016/j.jmmm.2025.173412","DOIUrl":"10.1016/j.jmmm.2025.173412","url":null,"abstract":"<div><div>Magnetic gears (MGs) have emerged as a compelling subject of research in recent years, owing to their distinct advantages over traditional mechanical gears. These benefits encompass the physical isolation between moving components, the elimination of gear lubrication, inherent overload protection, and reduced maintenance requirements. Although various MG topologies have been proposed, each exhibiting unique merits and drawbacks, the complexities arising from nonlinearities and magnetic hysteresis pose substantial challenges in their modeling and control. Extensive investigations into the position, speed, and torque control of MGs have been documented in the literature. This paper presents a comprehensive review of the latest developments in MGs modeling and control, with a particular emphasis on diverse modeling approaches and control strategies. Moreover, the article critically addresses the current limitations and challenges in this domain and outlines promising avenues for future research, highlighting the synergy between theoretical advancements and practical implementations, and underscoring the significance of MGs as a transformative technology.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173412"},"PeriodicalIF":3.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of linear and non-linear electron–phonon interactions on impurity bound states in BCS superconductor","authors":"B. Navashreya ,&nbsp;Narasimha Raju Chebrolu ,&nbsp;Anusha Kachu ,&nbsp;Aalu Boda","doi":"10.1016/j.jmmm.2025.173433","DOIUrl":"10.1016/j.jmmm.2025.173433","url":null,"abstract":"<div><div>We have considered a quantum impurity with local electron–electron, linear, and quadratic electron–phonon interactions embedded in a Bardeen-Cooper-Schrieffer (BCS) superconducting medium, modeled by a single spin-degenerate impurity Anderson-Holstein model Hamiltonian. We have employed the canonical transformations combined with the Kikuchi–Morita Cluster variation (CV) method to analyze the conditions necessary in the superconductor for the formation of the magnetic moment, subgap Yu-Shiba-Rusinov bound state associated with the magnetic impurity, and transition from single to bipolaron at the impurity site as a function of electron–electron, linear and nonlinear electron–phonon interactions, and the superconducting gap. We have observed that the effective coupling between the electrons and phonons is reduced (enhanced), and the effective phonon frequency is hardened (softened) by a slight positive (negative) quadratic electron–phonon interaction. These results show that nonlinear electron–phonon interaction can significantly impact the physics of many electron–phonon coupled systems. They are critical for magnetic quantum impurities deposited on a metal with typical nonlinear coupling strengths.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173433"},"PeriodicalIF":3.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144828002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a critical endpoint in the valence fluctuating Eu(Rh1−xCox)2Si2 system","authors":"Franziska Walther ,&nbsp;Michelle Ocker ,&nbsp;Alexej Kraiker ,&nbsp;Nubia Caroca-Canales ,&nbsp;Silvia Seiro ,&nbsp;Christoph Geibel ,&nbsp;Kristin Kliemt ,&nbsp;Cornelius Krellner","doi":"10.1016/j.jmmm.2025.173417","DOIUrl":"10.1016/j.jmmm.2025.173417","url":null,"abstract":"<div><div>We report on the successful single crystal growth of pure EuRh₂Si₂ and of Eu(Rh<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Co<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>)₂Si₂ with <span><math><mrow><mi>x</mi><mo>≤</mo><mn>0</mn><mo>.</mo><mn>23</mn></mrow></math></span> by the flux method. Through Co substitution, EuRh₂Si₂ can be tuned from stable antiferromagnetism via a valence-transition state towards the valence-crossover regime. From magnetization measurements, we constructed a <span><math><mrow><mi>B</mi><mo>−</mo><mi>T</mi></mrow></math></span> phase diagram for EuRh₂Si₂ comprising multiple magnetic phases and showing a sizeable magnetic anisotropy within the basal plane of the tetragonal unit cell. This indicates a complex antiferromagnetic ground state for <span><math><mrow><mi>x</mi><mo>=</mo><mn>0</mn></mrow></math></span>. By applying positive chemical pressure through the substitution series Eu(Rh<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Co<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span>)₂Si₂, a sharp temperature-induced first-order phase transition is observed in magnetization, resistivity and heat capacity for 0.081 <span><math><mo>≤</mo></math></span> <span><math><mi>x</mi></math></span> <span><math><mo>≤</mo></math></span> 0.126. The critical end point of this valence transition is located in the phase diagram in the vicinity of 0.126 <span><math><mrow><mo>&lt;</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>EDX</mi></mrow></msub><mo>&lt;</mo></mrow></math></span> 0.23. At higher substitution level, the system reaches a valence-crossover regime. The obtained results are presented in a temperature-substitution phase diagram.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173417"},"PeriodicalIF":3.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144827999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploration of magnetocaloric properties in LaFeO3 perovskite: A mean-field theory combined with the Ising model","authors":"E.M. Jalal ,&nbsp;M. Salama ,&nbsp;H. Kerrai ,&nbsp;H. Saadi ,&nbsp;A. Lafhal ,&nbsp;A. Hasnaoui ,&nbsp;M. El Bouziani","doi":"10.1016/j.jmmm.2025.173424","DOIUrl":"10.1016/j.jmmm.2025.173424","url":null,"abstract":"<div><div>In this study, we investigate the magnetocaloric effect and magnetothermal properties of the LaFeO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> compound using mean field approximation by examining its behavior as a function of temperature and applied magnetic field. We begin by detailing the model, methodology, and magnetic stability of LaFeO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>, followed by determining the transition temperature through analyses of magnetization, the susceptibility and the isothermal entropy change -<span><math><mrow><mi>Δ</mi><msub><mrow><mi>S</mi></mrow><mrow><mi>m</mi></mrow></msub></mrow></math></span>. Our temperature-dependent magnetization analysis reveals a second order antiferromagnetic to paramagnetic phase transition occurring at 720 K, consistent with previous experimental and theoretical studies. The change of magnetic entropy increases monotonically with applied magnetic field and reaches the values of 0.26 J/kg K and −0.6 J/kg K at 700 K and 720 K, respectively, in an applied field of 0–5 T, with a refrigerant capacity value of 70.04 J/kg and 28.8 J/kg at 700 K and 720 K, respectively. It was found inverse and direct magnetocaloric effect. These findings offer deeper insight into the magnetic behavior of LaFeO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> and highlight its relevance as a model system for exploring magnetocaloric effects in iron perovskites.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173424"},"PeriodicalIF":3.0,"publicationDate":"2025-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144809823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}