Pub Date : 2017-03-31DOI: 10.9714/psac.2017.19.1.001
K. W. Kim
Forefront ultrafast experimental techniques have recently proven their potential as new approaches to understand materials based on non-equilibrium dynamics in the time domain. The time domain approach is useful especially in disentangling complicated coupling among charge, spin and lattice degrees of freedom. Various ultrafast experiments on Fe-based superconductors have observed strong coherent oscillations of an A 1g phonon mode of arsenic ions, which shows strong coupling to the electronic and magnetic states. This paper reviews the recent reports of ultrafast studies on Fe-based superconductor with a focus on the coherent oscillations. Experimental results with ultrashort light sources from the terahertz-infrared pulses to the hard X-rays from a free electron laser will be presented.
{"title":"Ultrafast probes of coherent oscillations in Fe-based superconductors","authors":"K. W. Kim","doi":"10.9714/psac.2017.19.1.001","DOIUrl":"https://doi.org/10.9714/psac.2017.19.1.001","url":null,"abstract":"Forefront ultrafast experimental techniques have recently proven their potential as new approaches to understand materials based on non-equilibrium dynamics in the time domain. The time domain approach is useful especially in disentangling complicated coupling among charge, spin and lattice degrees of freedom. Various ultrafast experiments on Fe-based superconductors have observed strong coherent oscillations of an A 1g phonon mode of arsenic ions, which shows strong coupling to the electronic and magnetic states. This paper reviews the recent reports of ultrafast studies on Fe-based superconductor with a focus on the coherent oscillations. Experimental results with ultrashort light sources from the terahertz-infrared pulses to the hard X-rays from a free electron laser will be presented.","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"1-4"},"PeriodicalIF":0.3,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43800451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-03-31DOI: 10.9714/PSAC.2017.19.1.030
Y. Jung, S. Go, H. Joo, Y. J. Lee, S.-D. Park, B. Jun, C. Kim
2017) Abstract The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces ( F ) and trapped magnetic field ( B ) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance ( F-d ) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density ( J c ) of the (001) surface. For the (001) samples with t =5 – 18 mm, the maximum magnetic levitation forces ( F max s) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness ( t =5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic
{"title":"Orientation and thickness dependence of magnetic levitation force and trapped magnetic field of single grain YBa2Cu3O7-y bulk superconductors","authors":"Y. Jung, S. Go, H. Joo, Y. J. Lee, S.-D. Park, B. Jun, C. Kim","doi":"10.9714/PSAC.2017.19.1.030","DOIUrl":"https://doi.org/10.9714/PSAC.2017.19.1.030","url":null,"abstract":"2017) Abstract The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces ( F ) and trapped magnetic field ( B ) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance ( F-d ) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density ( J c ) of the (001) surface. For the (001) samples with t =5 – 18 mm, the maximum magnetic levitation forces ( F max s) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness ( t =5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"30-35"},"PeriodicalIF":0.3,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43806930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-03-31DOI: 10.9714/PSAC.2017.19.1.042
Sang-Hyun Kim, W. Kang, Y. J. Lee, B. Jun, C. Kim
2017) Abstract The effects of the heat treatment temperature (600 ℃ -1050 ℃ ) on the formation of MgB 2 and the superconducting properties have been examined. The self-synthesized MgB 4 and commercial Mg powders were used as raw materials for the formation of MgB 2 . The superconducting critical temperatures ( T c s) of MgB 2 bulk superconductors prepared at 600 ℃ -850 ℃ were as high as 37-38 K regardless of the heat treatment temperature. However, because MgB 4 is more stable than MgB 2 at above 850 ℃ , no superconducting signals were detected in the susceptibility-temperature curves of the samples prepared above 850 ℃ . As for the critical current density ( J c ), the sample heat-treated at a low temperature (600 ℃ ) for a prolonged period (40 h) showed a J c higher than those prepared at 650 ℃ -850 ℃ for a short period (1 h). The FWHM (full width at half maximum) result showed that the grain size of MgB 2 of the 600 ℃ sample was smaller than that of the other samples. The high J c of the 600 ℃ sample is attributed to the presence of large numbers of grain boundaries, which can act as flux pinning centers of MgB 2
{"title":"Effects of heat treatment temperature on the formation of MgB 2 bulk superconductors prepared using MgB 4 and Mg powder","authors":"Sang-Hyun Kim, W. Kang, Y. J. Lee, B. Jun, C. Kim","doi":"10.9714/PSAC.2017.19.1.042","DOIUrl":"https://doi.org/10.9714/PSAC.2017.19.1.042","url":null,"abstract":"2017) Abstract The effects of the heat treatment temperature (600 ℃ -1050 ℃ ) on the formation of MgB 2 and the superconducting properties have been examined. The self-synthesized MgB 4 and commercial Mg powders were used as raw materials for the formation of MgB 2 . The superconducting critical temperatures ( T c s) of MgB 2 bulk superconductors prepared at 600 ℃ -850 ℃ were as high as 37-38 K regardless of the heat treatment temperature. However, because MgB 4 is more stable than MgB 2 at above 850 ℃ , no superconducting signals were detected in the susceptibility-temperature curves of the samples prepared above 850 ℃ . As for the critical current density ( J c ), the sample heat-treated at a low temperature (600 ℃ ) for a prolonged period (40 h) showed a J c higher than those prepared at 650 ℃ -850 ℃ for a short period (1 h). The FWHM (full width at half maximum) result showed that the grain size of MgB 2 of the 600 ℃ sample was smaller than that of the other samples. The high J c of the 600 ℃ sample is attributed to the presence of large numbers of grain boundaries, which can act as flux pinning centers of MgB 2","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"42-46"},"PeriodicalIF":0.3,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43201912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-03-31DOI: 10.9714/PSAC.2017.19.1.051
Geonwoo Baek, Jinsub Kim, W. Lee, Seunghyun Song, Onyou Lee, Hyoungku Kang, T. Ko
2017) Abstract To obtain Nuclear Magnetic Resonance (NMR) measurement of membrane protein, an NMR magnet is required to generate high intensity, homogeneity, and stability of field. A High-Temperature Superconducting (HTS) magnet is a promising alternative to a conventional Low-Temperature Superconducting (LTS) NMR magnet for high field, current density, and stability margin. Conventionally, an HTS coil has been wound by several winding techniques such as Single-Pancake (SP), Double-Pancake (DP), and layer-wound. The DP winding technique has been frequently used for a large magnet because long HTS wire is generally difficult to manufacture, and maintenance of magnet is convenient. However, magnetic field generated by the slanted turns and the splice leads to field inhomogeneity in Diameter of Spherical Volume (DSV). The field inhomogeneity degrades performance of NMR spectrometer and thus effect of the slanted turns and the splice should be analyzed. In this paper, field gradient of HTS double-pancake coils considering the slanted turns and the splice was calculated using Biot-Savart law and numerical integration. The calculation results showed that magnetic field produced by the slanted turns and the splice caused significant inhomogeneity of
{"title":"Field gradient calculation of HTS double-pancake coils considering the slanted turns and the splice","authors":"Geonwoo Baek, Jinsub Kim, W. Lee, Seunghyun Song, Onyou Lee, Hyoungku Kang, T. Ko","doi":"10.9714/PSAC.2017.19.1.051","DOIUrl":"https://doi.org/10.9714/PSAC.2017.19.1.051","url":null,"abstract":"2017) Abstract To obtain Nuclear Magnetic Resonance (NMR) measurement of membrane protein, an NMR magnet is required to generate high intensity, homogeneity, and stability of field. A High-Temperature Superconducting (HTS) magnet is a promising alternative to a conventional Low-Temperature Superconducting (LTS) NMR magnet for high field, current density, and stability margin. Conventionally, an HTS coil has been wound by several winding techniques such as Single-Pancake (SP), Double-Pancake (DP), and layer-wound. The DP winding technique has been frequently used for a large magnet because long HTS wire is generally difficult to manufacture, and maintenance of magnet is convenient. However, magnetic field generated by the slanted turns and the splice leads to field inhomogeneity in Diameter of Spherical Volume (DSV). The field inhomogeneity degrades performance of NMR spectrometer and thus effect of the slanted turns and the splice should be analyzed. In this paper, field gradient of HTS double-pancake coils considering the slanted turns and the splice was calculated using Biot-Savart law and numerical integration. The calculation results showed that magnetic field produced by the slanted turns and the splice caused significant inhomogeneity of","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"51-55"},"PeriodicalIF":0.3,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45235317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-03-31DOI: 10.9714/PSAC.2017.19.1.017
S. He, Changqiao Yang, Suqin Li, Changquan Zhang
Vanadium slags is a kind of vanadiferous solid waste from steelmaking process. It not only occupies land, pollutes environment, but also leads to waste of resources. Based on the difference of magnetic susceptibility of different particles caused by their chemical and physical properties from vanadium slag, a new technology, superconducting high gradient magnetic separation was investigated for separation and extraction of valuable substances from vanadium slag. The magnetic concentrate was obtained under optimal parameters, i.e., a particle size -200 mesh, a magnetic flux density of 0.8 T, a slurry concentration of 5 g/L, an amount of steel wools of 25 g and a slurry flow velocity of 2 L/min. The content of Fe2O3 in concentrate could be increased from 39.6% to 55.0% and V2O5 from 2.5% to 4.0%, respectively. The recovery rate is up to 42.9%, and the vanadium slag has been effectively reused.
{"title":"Enrichment of valuable elements from vanadium slag using superconducting HGMS technology","authors":"S. He, Changqiao Yang, Suqin Li, Changquan Zhang","doi":"10.9714/PSAC.2017.19.1.017","DOIUrl":"https://doi.org/10.9714/PSAC.2017.19.1.017","url":null,"abstract":"Vanadium slags is a kind of vanadiferous solid waste from steelmaking process. It not only occupies land, pollutes environment, but also leads to waste of resources. Based on the difference of magnetic susceptibility of different particles caused by their chemical and physical properties from vanadium slag, a new technology, superconducting high gradient magnetic separation was investigated for separation and extraction of valuable substances from vanadium slag. The magnetic concentrate was obtained under optimal parameters, i.e., a particle size -200 mesh, a magnetic flux density of 0.8 T, a slurry concentration of 5 g/L, an amount of steel wools of 25 g and a slurry flow velocity of 2 L/min. The content of Fe2O3 in concentrate could be increased from 39.6% to 55.0% and V2O5 from 2.5% to 4.0%, respectively. The recovery rate is up to 42.9%, and the vanadium slag has been effectively reused.","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"17-21"},"PeriodicalIF":0.3,"publicationDate":"2017-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44946199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-01-01DOI: 10.9714/psac.2017.19.3.013
J. Oh, H. Jeon, J. M. Lee, W. Kang, B. Kang
We investigated the effect of self-assembled BSO nano-defects as pinning centers in BSO-added GdBCO films when the thicknesses of films were varied. 3.5 vol. % BSO-added GdBCO films with varying thicknesses from 200 nm to 1000 nm were deposited on SrTiO 3 (STO) substrate by using pulsed laser deposition (PLD) process. For the films with thicknesses of 400 nm and 600 nm, ‘anomaly shoulders’ in J c - H characteristic curves were observed near the matching field. The anomaly shoulders appeared in the field dependence of J c may be attributed to the existence of double pinning mechanisms in thin films. The fit to the pinning force density as a function of reduced field h (H/H irr ) using the Dew-Hughes’ scaling law shows that both the 400 nm- and the 600 nm-thick films have double pinning mechanisms while the other films have a single pinning mechanism. These results indicate that the self-assembled property of BSO result in different role as pinning centers with different thickness.
我们研究了自组装BSO纳米缺陷作为钉钉中心对添加BSO的GdBCO薄膜的影响。采用脉冲激光沉积(PLD)工艺，在srtio_3 (STO)衬底上沉积了3.5 vol. % bso的GdBCO薄膜，薄膜厚度从200 nm到1000 nm不等。对于厚度为400 nm和600 nm的薄膜，在匹配场附近观察到J - c - H特征曲线的“异常肩”。在J c场依赖中出现的异常肩可能是由于薄膜中存在双钉钉机制。利用Dew-Hughes标度定律拟合钉钉力密度随减小场h (h / h irr)的函数，结果表明，400 nm和600 nm厚的薄膜都具有双钉钉机制，而其他薄膜则具有单钉钉机制。这些结果表明，BSO的自组装特性导致了不同厚度的BSO作为固定中心的作用不同。
{"title":"Effect of double pinning mechanism in BSO-added GdBa 2 Cu 3 O 7-x thin films","authors":"J. Oh, H. Jeon, J. M. Lee, W. Kang, B. Kang","doi":"10.9714/psac.2017.19.3.013","DOIUrl":"https://doi.org/10.9714/psac.2017.19.3.013","url":null,"abstract":"We investigated the effect of self-assembled BSO nano-defects as pinning centers in BSO-added GdBCO films when the thicknesses of films were varied. 3.5 vol. % BSO-added GdBCO films with varying thicknesses from 200 nm to 1000 nm were deposited on SrTiO 3 (STO) substrate by using pulsed laser deposition (PLD) process. For the films with thicknesses of 400 nm and 600 nm, ‘anomaly shoulders’ in J c - H characteristic curves were observed near the matching field. The anomaly shoulders appeared in the field dependence of J c may be attributed to the existence of double pinning mechanisms in thin films. The fit to the pinning force density as a function of reduced field h (H/H irr ) using the Dew-Hughes’ scaling law shows that both the 400 nm- and the 600 nm-thick films have double pinning mechanisms while the other films have a single pinning mechanism. These results indicate that the self-assembled property of BSO result in different role as pinning centers with different thickness.","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"13-17"},"PeriodicalIF":0.3,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-01-01DOI: 10.9714/PSAC.2017.19.4.026
Shin Hyung Seop, Mark Angelo Diaz, Jae-Hun Lee
{"title":"Characterization of electromechanical properties of Sn-Cu double layer stabilized GdBCO coated conductor tapes at 77 K","authors":"Shin Hyung Seop, Mark Angelo Diaz, Jae-Hun Lee","doi":"10.9714/PSAC.2017.19.4.026","DOIUrl":"https://doi.org/10.9714/PSAC.2017.19.4.026","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"26-30"},"PeriodicalIF":0.3,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-01-01DOI: 10.9714/PSAC.2017.19.2.014
H. Lee
{"title":"Interior seeding combined with top seeding for the fabrication of single grain REBCO bulk superconductors","authors":"H. Lee","doi":"10.9714/PSAC.2017.19.2.014","DOIUrl":"https://doi.org/10.9714/PSAC.2017.19.2.014","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"14-18"},"PeriodicalIF":0.3,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-01-01DOI: 10.9714/psac.2017.19.2.009
H. Lee
{"title":"Effects of seed orientation on the growth behavior of single grain REBCO bulk superconductors","authors":"H. Lee","doi":"10.9714/psac.2017.19.2.009","DOIUrl":"https://doi.org/10.9714/psac.2017.19.2.009","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"9-13"},"PeriodicalIF":0.3,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-01-01DOI: 10.9714/PSAC.2017.19.3.033
Hwi-Joo Lee, Park Soondong, B. Jun, Chan-Joon Kim, H. Lee
{"title":"Effects of seed geometry on the crystal growth and the magnetic properties of single grain REBCO bulk superconductors","authors":"Hwi-Joo Lee, Park Soondong, B. Jun, Chan-Joon Kim, H. Lee","doi":"10.9714/PSAC.2017.19.3.033","DOIUrl":"https://doi.org/10.9714/PSAC.2017.19.3.033","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"19 1","pages":"33-39"},"PeriodicalIF":0.3,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：