{"title":"Significant improvement of Jc and flux pinning force of MgB2 by doping NTE-ZrW2O8 particles","authors":"Tianqi Weng, Lingkai Yuan, Chuan Ke, Cui Hua Cheng, Yong Zhao","doi":"10.1016/j.jma.2025.02.029","DOIUrl":null,"url":null,"abstract":"Although introducing second phase particles as additional pinning centers is an effective method to improve the current carrying capacity of MgB<sub>2</sub>, the thermal strain caused by second phase particles in MgB<sub>2</sub> and their impact on flux pinning have not received much attention. In this paper, flux pinning behavior of the thermal strain induced by the second phase particles in the MgB<sub>2</sub> bulk materials was studied by doping ZrW<sub>2</sub>O<sub>8</sub> particles which have negative thermal expansion (NTE) characteristics. Due to the significant difference in thermal expansion characters between ZrW<sub>2</sub>O<sub>8</sub> and MgB<sub>2</sub>, drastic thermal strain was induced in the lattice of MgB<sub>2</sub> by doping the NTE-ZrW<sub>2</sub>O<sub>8</sub> particles. These strains work as additional flux pinning centers and significantly enhance the irreversibility field, <em>H</em><sub>irr</sub>, and critical current density, <em>J</em><sub>c</sub>, of the MgB<sub>2</sub>. Taking <em>J</em><sub>c</sub> as an example, at 4.2 K and 5 T, its <em>J</em><sub>c</sub> value reaches 4.1 × 10<sup>4</sup> A/cm<sup>2</sup>, which is a 105 % performance improvement compared to the 2.0 × 10<sup>4</sup> A/cm<sup>2</sup> of the pure MgB<sub>2</sub> sample W-0; at 20 K and 2 T, its <em>J</em><sub>c</sub> also reaches 1.3 × 10<sup>5</sup> A/cm<sup>2</sup>, which is 1.78 times of the 7.3 × 10<sup>4</sup> A/cm<sup>2</sup> for the pure MgB<sub>2</sub> sample under the same conditions. It is interesting that doping ZrW<sub>2</sub>O<sub>8</sub> does not significantly change the scaling behavior of the pinning force, indicating that the lattice strain work like surficial pinning center, while the point defect pinning center initiated by ZrW<sub>2</sub>O<sub>8</sub> particles themselves may only contribute to the high field region, causing the peak in the pinning force scaling curve to shift towards higher fields.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":"8 1","pages":""},"PeriodicalIF":15.8000,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Magnesium and Alloys","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1016/j.jma.2025.02.029","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"METALLURGY & METALLURGICAL ENGINEERING","Score":null,"Total":0}
引用次数: 0
Abstract
Although introducing second phase particles as additional pinning centers is an effective method to improve the current carrying capacity of MgB2, the thermal strain caused by second phase particles in MgB2 and their impact on flux pinning have not received much attention. In this paper, flux pinning behavior of the thermal strain induced by the second phase particles in the MgB2 bulk materials was studied by doping ZrW2O8 particles which have negative thermal expansion (NTE) characteristics. Due to the significant difference in thermal expansion characters between ZrW2O8 and MgB2, drastic thermal strain was induced in the lattice of MgB2 by doping the NTE-ZrW2O8 particles. These strains work as additional flux pinning centers and significantly enhance the irreversibility field, Hirr, and critical current density, Jc, of the MgB2. Taking Jc as an example, at 4.2 K and 5 T, its Jc value reaches 4.1 × 104 A/cm2, which is a 105 % performance improvement compared to the 2.0 × 104 A/cm2 of the pure MgB2 sample W-0; at 20 K and 2 T, its Jc also reaches 1.3 × 105 A/cm2, which is 1.78 times of the 7.3 × 104 A/cm2 for the pure MgB2 sample under the same conditions. It is interesting that doping ZrW2O8 does not significantly change the scaling behavior of the pinning force, indicating that the lattice strain work like surficial pinning center, while the point defect pinning center initiated by ZrW2O8 particles themselves may only contribute to the high field region, causing the peak in the pinning force scaling curve to shift towards higher fields.
期刊介绍:
The Journal of Magnesium and Alloys serves as a global platform for both theoretical and experimental studies in magnesium science and engineering. It welcomes submissions investigating various scientific and engineering factors impacting the metallurgy, processing, microstructure, properties, and applications of magnesium and alloys. The journal covers all aspects of magnesium and alloy research, including raw materials, alloy casting, extrusion and deformation, corrosion and surface treatment, joining and machining, simulation and modeling, microstructure evolution and mechanical properties, new alloy development, magnesium-based composites, bio-materials and energy materials, applications, and recycling.