  Diamond is an excellent band insulator. However, boron (B) doping is known to
induce superconductivity. We present two interesting effects in superconducting
B doped diamond (BDD) thin films: i) Wohlleben effect (paramagnetic Meissner
effect, PME) and ii) a low field spin glass like susceptibility anomaly. We
have performed electrical and magnetic measurements (under pressure in one
sample) at dopings (1.4 , 2.6 and 3.6) X 1021 cm-3, in a temperature range 2 -
10 K. PME, a low field anomaly in inhomogeneous superconductors could arise
from flux trapping, flux compression, or for non-trivial reason such as
emergent Josephson Pi junctions. Joint occurrence of PME and spin glass type
anomalies points to possible emergence of Pi junctions. BDD is a disordered
s-wave superconductor; and Pi junctions could be produced by spin flip
scattering of spin half moments when present at weak superconducting regions
(Bulaevski et al. 1978). A frustrated network of 0 and Pi junctions will result
(Kusmartsev et al. 1992) in a distribution of spontaneous equilibrium
supercurrents, a phase glass state. Anderson localized spin half spinons
embedded in a metallic fluid (two fluid model of Bhatt et al.) could create Pi
junction by spin flip scattering. Our findings are consistent with presence of
Pi junctions, invoked to explain their (Bhattacharyya et al.) observation of
certain resistance anomaly in BDD.
