| Bulk MgB2(+C) was prepared via in-situ or ex-situ reaction during conventional sintering or spark-plasma sintereing (SPS). The SPSed samples resulted in a much higher densification than the sintered one. As a result, higher the critical current densiy values were reported for the SPS samples. In-situ reacted SPS samples generally exhibited a higher critical density than the ex-situ processed ones at low magnetic fields, but degradaded more quickly at higher fields than 3 T. The ex-situ reacted SPS samples with 5% excess C showed the critical current density up to 18,000 A/cm2 at 5 T (5K). |
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