Figure 6

Maximum trapped field as a function of normalised temperature for (a) 5% B4C (MPIG) (b) 10% B4C (MPIG) bulk MgB2 superconducting discs. Data for undoped MPIG bulk samples measured in the same configuration are also shown (c) Trapped field dependence with normalised temperature for a stack arrangement (Stack-5). The location of the hall probe(s) is shown in the insets and an image of representative bulk shown in (a). H1 was placed in the middle of gap (1.6 mm) between the two bulks.