Dehydrogenation-induced crystal defects for significant enhancement of critical current density in polycrystalline H-doped MgB2

Confinement of self-generated Mg(BH4)2 particles for simultaneously enhanced flux pinning and grain connectivity in polycrystalline H-doped MgB2

“…In addition to the MgO, Mg(BH 4 ) 2 phase was produced in the H-doped samples. The formation of the Mg(BH 4 ) 2 phases was also proved in our previous studies [18,19]. When the H-doped samples experienced different cooling modes, the Mg(BH 4 ) 2 phases were in different crystal structures.…”

“…The control of amorphous impurities led to the enhancement of the transport J c ; however, the in-field J c of MgB 2 decreased when a large fraction of the dopant was used. In our previous study, we proposed the 'clean' H doping method to introduce a self-generated phase instead of the exotic impurities [18,19]. Although the intergranular current-interrupted impurities were removed and the refined Mg(BH 4 ) 2 particles were forced to a uniform distribution inside the MgB 2 grains, the low-field J c still decreased.…”