Enhanced Critical Current Density in Bulk MgB<sub>2</sub>

Muralidhar, M.; Higuchi, Masaki; Kitamoto, K.; Koblischka, Michael Rudolf; Jirsa, M.; Murakami, Masato

doi:10.1109/tasc.2018.2793309

Cited by 10 publications

(3 citation statements)

References 23 publications

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“…This is due to amorphous nano boron precursor that was used. The nano boron precursor results in nano-sized MgB 2 grains in the final bulk leading to high grain boundary pinning which acts specifically at low fields [7].…”

Section: Resultsmentioning

confidence: 99%

“…[4,5]. However, additional enhancement of flux pinning and critical current density (J c ) is significant for material compatibility at high-field applications as MgB 2 superconducting material consists of weak flux pinning and poor grain connectivity which would further lead to a sharp fall in critical current density at higher magnetic fields around 20 K [6,7]. In particular, doping and chemical addition with C or C-based compounds in MgB 2 contributed towards the improvement of critical current density performance due to amelioration of intra-band scattering and grain connectivity as well as the induction of extra pinning centers [8].…”

Section: Introductionmentioning

confidence: 99%

“…In order to overcome this issue, researchers had introduced carbon-encapsulated boron for a batch production of MgB 2 samples and proved to be successful. In contrast, carbon-encapsulated boron powder was considered to be expensive making the entire fabrication process costly and was not a preferable option for a commercial production of bulk MgB 2 super-magnets [7]. Due to the following reasons, "synthetic motor oil" was utilized because it was considered to be a rich source of carbon since it could be easily accessed at a relatively cheaper price and was suggested to be a viable alternative towards low cost processing for industrial approach; as a matter of fact, synthetic motor oil produces a high tolerance towards aging and heat as it poses high oxidative and high thermal stability.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Flux Pinning Performance of Bulk MgB2 via Immersion of Synthetic Motor Oil

Santosh

Arvapalli

Muralidhar

2022

J Supercond Nov Magn

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The present investigation focuses on the incorporation of synthetic motor oil as an inexpensive, rich carbon source in bulk MgB2 superconductor and its effect on superconducting and flux pinning properties. A set of three MgB2 bulk samples were prepared from commercial high-purity powders of Mg metal and amorphous B powder utilizing a conventional in situ solid-state reaction process. Before sintering, the MgB2 samples were immersed in used and new synthetic motor oil for a standby time of 30 min and sintered in pure Ar atmosphere at 775 °C for 3 h. X-ray powder diffractometer (XRD) analysis confirmed that single-phase formation of MgB2 with a small shift in X-ray diffraction peaks especially at (110) towards the peak position due to the effect of carbon substitution into the boron sites in lattice for samples immersed in new and used synthetic oil. The magnetization measurements indicated the Tc (onset) value to somewhat decrease to 37.5 K as a result of carbon doping. Microstructural observations with scanning electron microscopy (SEM) suggested that fine nano-sized MgB2 grains improved self-field critical current density around 3.8 × 105 A/cm2 at 20 K for all samples studied. Further, the high-field critical current density (Jc) was improved especially for the sample immersed in used synthetic motor oil with the value of 2.7 × 104 A/cm2, 6 × 103 A/cm2 at 20 K, and at 3 T and 4 T, which is higher as compared to pure-MgB2 sample. In essence, the results signify that the bulk MgB2 samples immersed with used synthetic motor oil would improve the bulk performance at high magnetic fields indicating to be a viable option for industrial applications.

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Section: Resultsmentioning

confidence: 99%