The effect of magnesium vacancies on the π intraband scattering in Mgx B2 as determined by point contact Andreev reflection

Abstract

In order to introduce structural defects into the π band with minimal distortions in the band, bulk samples of varying magnesium content were prepared. Point contact Andreev reflection measurements reveal that the density of states of the π band and the behavior of the energy gaps in field imply a relative increase of π band to band scattering with increasing magnesium deficiency. The results are consistent with the observed increase of the low temperature Hc2 value in magnesium deficient Mg B2. © 2007 American Institute of Physics.