Role of double doping with C and RE 2 O 3 oxides on the critical temperature and critical current of MgB 2 phase

Gajda, Grzegorz; Morawski, A.; Diduszko, R.; Cetner, T.; Hossain, Md. Shahriar A.; Gruszka, K.; Gajda, D.; Przysłupski, P.

doi:10.1016/j.jallcom.2017.03.159

Cited by 21 publications

(9 citation statements)

References 22 publications

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“…Studies also showed that high isostatic pressure increases the number of connections between the grains densifying material [31,36]. Transport and magnetic measurements have demonstrated that highfield pinning centers (dislocations and strains) significantly increase J c from 4.2 to 30 K and decrease J c above 30 K [21,36,72].…”

Section: Physical Properties and Pinning Centers In Mgb 2 Wiresmentioning

confidence: 99%

“…These pinning centers are most effective for increasing critical current density in low and medium magnetic fields [18][19][20]. In addition, Gajda et al [21] showed that these pinning centers in MgB 2 increase the critical current density (J c ) above 30 K, whereas pinning centers created by dislocations (line pinning centers) [2], substitution of C for B (lattice substitution pinning centers) [22], and precipitates inside the grain (inside grains pinning centers) [23] very effectively increase the J c in high magnetic fields [18]. These pinning centers also significantly increase J c from 4.2 to 30 K and decrease J c above 30 K in MgB 2 [21].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, Gajda et al [21] showed that these pinning centers in MgB 2 increase the critical current density (J c ) above 30 K, whereas pinning centers created by dislocations (line pinning centers) [2], substitution of C for B (lattice substitution pinning centers) [22], and precipitates inside the grain (inside grains pinning centers) [23] very effectively increase the J c in high magnetic fields [18]. These pinning centers also significantly increase J c from 4.2 to 30 K and decrease J c above 30 K in MgB 2 [21]. Gajda et al [18] suggested that precipitates inside grains in NbTi do not reduce the critical parameters: the superconducting critical temperature (T c ), the irreversible magnetic field (B irr ), and the upper critical field (B c2 ) of NbTi grains, and they effectively increase J c in magnetic fields above 9.5 T. Previous results suggest that the dislocations and substitution into the lattice (e.g., in MgB 2 material, the substitution of C for B) create pinning centers, which operate in the same high magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

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Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Gajda

2018

J Low Temp Phys

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The main purpose of this article is to show an easier and more accurate method for analyzing high-field pinning centers. Previous methods did not allow for precise analysis and research on high-field pinning centers, they studied only the dominant pinning mechanism, and they required a maximum of pinning force (F pmax) to analyze pinning centers. The main advantage of this method can be used in samples without the maximum pinning force required by other methods to analyze the pinning mechanism. In addition, this method allows us to observe even small changes in the density of individual pinning centers. This method is based on analysis of critical current density values in different ranges of reduced magnetic field. The method of analysis of highfield pinning centers allows primarily to develop methods and directions for creation of high-field pinning centers. The surface pinning centers are strong pinning centers in low magnetic fields and very weak pinning centers in middle and high magnetic fields. Additionally, the analysis of pinning centers shows that dislocations, strains, substitutions in the crystal lattice, and precipitation inside the grains create strong pinning centers in high magnetic fields and very weak pinning centers in low and middle magnetic fields. Research indicates that strains, substitutions in the crystal lattice, and precipitates inside grains form pinning centers that operate in the high magnetic field range.

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Section: Physical Properties and Pinning Centers In Mgb 2 Wiresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Gajda

2018

J Low Temp Phys

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“…The plot of I UC versus P pump with a double logarithmic scale yields a straight line with a slope n. Figure 6c shows the logarithmic plot of sample Rb-3. The values of n are 2.016 and 1.785 for the green and red emissions, which indicates that the green and red emissions are both two-photon processes [26]. The peak area integrals of the green and red emissions are shown in Figure 6b.…”

Section: Pl Luminescencementioning

confidence: 93%

Effect of Rb+ Doping on Tunable Luminescence in Yb3+/Er3+–Y2O3 Film

Song

et al. 2020

Coatings

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In this paper, a series of Rb+-doped Er3+/Yb3+–Y2O3 films were synthesized via a sol-gel method and spin coating. The structure and morphology of the samples were investigated by X-ray diffraction and scanning electron microscopy. The Rb+-doped films with nanoparticles, in the size range of 20–40 nm, were obtained. The spectroscopic analysis of the samples was investigated by using the emission spectra and the intensity of luminescence. All the samples exhibited a green emission ascribed to 2H11/2/4S3/2 to 4I15/2 of Er3+ and a red one ascribed to 4F9/2 and its stark level to 4I15/2 of Er3+. As the Rb+ concentration increased, the intensities of the green light and red light were enhanced 16.97- and 5.81-fold relative to that of the undoped sample. Moreover, by controlling the Rb+ concentration, the samples were capable of generating color-tunable luminescence from red to green linearly. The tunable emission was caused by the change of ion distribution ratio in 4F7/2(Er) and 4F9/2(Er) levels. The results suggest that the as-prepared Rb+-doped Er3+/Yb3+–Y2O3 films have a great potential for applications of luminescence.

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“…This in turn causes a reduction in the connections between grains and creates surface pinning centers that significantly decrease the critical current density (J c ) in middle and high magnetic fields [7,8]. Doping, e.g., SiC and C, promotes middle and high pinning centers, which increase J c in middle and high magnetic fields [7,[9][10][11][12]. SiC doping is more effective for increasing J c in high magnetic fields; however, it decreases the critical temperature (T c ) [8,13,14] and increases the irreversibility magnetic fields (B irr ) and upper magnetic fields (B c2 ) [8,10,[15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Effect of Heat Treatments under High Isostatic Pressure on the Transport Critical Current Density at 4.2 K and 20 K in Doped and Undoped MgB2 Wires

et al. 2021

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Annealing undoped MgB2 wires under high isostatic pressure (HIP) increases transport critical current density (Jtc) by 10% at 4.2 K in range magnetic fields from 4 T to 12 T and significantly increases Jtc by 25% in range magnetic fields from 2 T to 4 T and does not increase Jtc above 4 T at 20 K. Further research shows that a large amount of 10% SiC admixture and thermal treatment under a high isostatic pressure of 1 GPa significantly increases the Jtc by 40% at 4.2 K in magnetic fields above 6 T and reduces Jtc by one order at 20 K in MgB2 wires. Additionally, our research showed that heat treatment under high isostatic pressure is more evident in wires with smaller diameters, as it greatly increases the density of MgB2 material and the number of connections between grains compared to MgB2 wires with larger diameters, but only during the Mg solid-state reaction. In addition, our study indicates that smaller wire diameters and high isostatic pressure do not lead to a higher density of MgB2 material and more connections between grains during the liquid-state Mg reaction.

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Role of double doping with C and RE 2 O 3 oxides on the critical temperature and critical current of MgB 2 phase

Cited by 21 publications

References 22 publications

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

Effect of Rb+ Doping on Tunable Luminescence in Yb3+/Er3+–Y2O3 Film

Effect of Heat Treatments under High Isostatic Pressure on the Transport Critical Current Density at 4.2 K and 20 K in Doped and Undoped MgB2 Wires

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