Wenbin Jin, Fang Cheng, Nan Liu, Ruxin Song, Qingwen Meng, Zongqing Ma, Qiong Wu, Hongliang Ge
{"title":"逆转掺杂悖论:石墨烯空间嵌套增强了mgb2超导体的晶间连通性,同时诱导最小的转变温度下降。","authors":"Wenbin Jin, Fang Cheng, Nan Liu, Ruxin Song, Qingwen Meng, Zongqing Ma, Qiong Wu, Hongliang Ge","doi":"10.1088/1361-6528/ae0d97","DOIUrl":null,"url":null,"abstract":"<p><p>This study systematically investigates the influence of graphene (Gr) doping, pre-treatment, Cu co-doping, and sintering temperature on the microstructure and superconducting properties of MgB₂. Key findings reveal that Gr pre-treatment enhances dispersion homogeneity but only minimally affects coated boron powders. Low-temperature sintering with trace Cu facilitates finer grain control; however, Gr shifts the dominant reaction mechanism to the solid-solid (Mg-B) pathway, hindering Mg diffusion and causing incomplete reactions, even at elevated temperatures. System equilibrium necessitates prolonged low-temperature treatment or optimized doping. Crucially, the sample with 5 wt.% Gr + 5 wt.% Cu sintered at 800 °C shows a reduction in the full width at half maximum (FWHM) of the phonon density of states (PDOS) peak. This reduction arises from tensile strain induced by high-quality Gr, which counteracts residual stress and lattice distortion caused by carbon substitution, as indicated by mitigated Tc degradation in Raman and Tc measurements. Contrary to conventional understanding, we propose a primary enhancement mechanism involving the co-growth of MgB₂, Mg-Cu alloy, and amorphous phases on Gr micro-substrates. This co-growth fosters a dense, interconnected, and spatially nested architecture within the MgB₂ matrix, overcoming doping-induced poor intergranular connectivity and preventing low-field performance suppression.</p>","PeriodicalId":19035,"journal":{"name":"Nanotechnology","volume":" ","pages":""},"PeriodicalIF":2.8000,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Reversing the doping paradox: graphene spatial nesting enhances intergranular connectivity while inducing minimal transition temperature degradation in MgB<sub>2</sub>superconductors.\",\"authors\":\"Wenbin Jin, Fang Cheng, Nan Liu, Ruxin Song, Qingwen Meng, Zongqing Ma, Qiong Wu, Hongliang Ge\",\"doi\":\"10.1088/1361-6528/ae0d97\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>This study systematically investigates the influence of graphene (Gr) doping, pre-treatment, Cu co-doping, and sintering temperature on the microstructure and superconducting properties of MgB₂. Key findings reveal that Gr pre-treatment enhances dispersion homogeneity but only minimally affects coated boron powders. Low-temperature sintering with trace Cu facilitates finer grain control; however, Gr shifts the dominant reaction mechanism to the solid-solid (Mg-B) pathway, hindering Mg diffusion and causing incomplete reactions, even at elevated temperatures. System equilibrium necessitates prolonged low-temperature treatment or optimized doping. Crucially, the sample with 5 wt.% Gr + 5 wt.% Cu sintered at 800 °C shows a reduction in the full width at half maximum (FWHM) of the phonon density of states (PDOS) peak. This reduction arises from tensile strain induced by high-quality Gr, which counteracts residual stress and lattice distortion caused by carbon substitution, as indicated by mitigated Tc degradation in Raman and Tc measurements. Contrary to conventional understanding, we propose a primary enhancement mechanism involving the co-growth of MgB₂, Mg-Cu alloy, and amorphous phases on Gr micro-substrates. This co-growth fosters a dense, interconnected, and spatially nested architecture within the MgB₂ matrix, overcoming doping-induced poor intergranular connectivity and preventing low-field performance suppression.</p>\",\"PeriodicalId\":19035,\"journal\":{\"name\":\"Nanotechnology\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":2.8000,\"publicationDate\":\"2025-09-30\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Nanotechnology\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://doi.org/10.1088/1361-6528/ae0d97\",\"RegionNum\":4,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nanotechnology","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1088/1361-6528/ae0d97","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Reversing the doping paradox: graphene spatial nesting enhances intergranular connectivity while inducing minimal transition temperature degradation in MgB2superconductors.
This study systematically investigates the influence of graphene (Gr) doping, pre-treatment, Cu co-doping, and sintering temperature on the microstructure and superconducting properties of MgB₂. Key findings reveal that Gr pre-treatment enhances dispersion homogeneity but only minimally affects coated boron powders. Low-temperature sintering with trace Cu facilitates finer grain control; however, Gr shifts the dominant reaction mechanism to the solid-solid (Mg-B) pathway, hindering Mg diffusion and causing incomplete reactions, even at elevated temperatures. System equilibrium necessitates prolonged low-temperature treatment or optimized doping. Crucially, the sample with 5 wt.% Gr + 5 wt.% Cu sintered at 800 °C shows a reduction in the full width at half maximum (FWHM) of the phonon density of states (PDOS) peak. This reduction arises from tensile strain induced by high-quality Gr, which counteracts residual stress and lattice distortion caused by carbon substitution, as indicated by mitigated Tc degradation in Raman and Tc measurements. Contrary to conventional understanding, we propose a primary enhancement mechanism involving the co-growth of MgB₂, Mg-Cu alloy, and amorphous phases on Gr micro-substrates. This co-growth fosters a dense, interconnected, and spatially nested architecture within the MgB₂ matrix, overcoming doping-induced poor intergranular connectivity and preventing low-field performance suppression.
期刊介绍:
The journal aims to publish papers at the forefront of nanoscale science and technology and especially those of an interdisciplinary nature. Here, nanotechnology is taken to include the ability to individually address, control, and modify structures, materials and devices with nanometre precision, and the synthesis of such structures into systems of micro- and macroscopic dimensions such as MEMS based devices. It encompasses the understanding of the fundamental physics, chemistry, biology and technology of nanometre-scale objects and how such objects can be used in the areas of computation, sensors, nanostructured materials and nano-biotechnology.