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Schlagwörter:
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Zusammenfassung:
We present transverse field (TF) muon spin rotation (mu+SR) measurements
on single crystalline UPd2Al3 carried out in the temperature range 25
mK-300 K at different fields between 350 Oe and 10 kOe. For the magnetic
easy direction H perpendicular-to c-axis, the muon Knight shift shows a
deviation from linear scaling with the bulk susceptibility at T < 40 K,
the origin of which is unclear. TF-mu+SR in the T range 25 mK-2.5 K,
aimed at determining the temperature and angular dependence of the
penetration depth lambda, revealed unusual behaviour. While the observed
increase of the mu+SR depolarisation rates below T(c), caused by the
formation of the flux lattice, is field independent up to 10 kOe for H
parallel-to c-axis, it drastically reduces with increasing field for H
perpendicular-to c-axis. Assuming the formation of a regular flux
lattice for H parallel-to c a value of lambda = (4200 +/- 1500) angstrom
is deduced. For H perpendicular-to c, lambda = (4600 +/- 1500) angstrom
at 350 Oe. The muon Knight shift is reduced by the superconducting
transition, pointing to a reduction of the U-5f susceptibility of
almost-equal-to 20% at T--> 0.
