Search results

Sort By:

Limit search:

Thermoelectric Power of MgB_2 Single Crystals Doped with Holes and Electrons

100%

Oganisian K., Rogacki K., Sulkowski C., Zhigadlo N., Katrych S., Karpinski J.

Acta Physica Polonica A

2008

vol. 114

issue 1

191-195

The thermoelectric power of MgB_2 single crystals, non-substituted, single-substituted with C, and co-substituted with C and Li, was investigated in the temperature range from 10 to 300 K. Both the in-plane (S_ab) and the out-of-plane (S_c) thermoelectric powers are positive for non-substituted crystals and both S_ab and S_c change a sign for crystals doped with electrons when C is substituted for B in the amount larger than 6 at.%. The substitution of C, which supplies electrons mainly into the σ band, reduces the thermoelectric power anisotropy, most likely by increasing the interband scattering. When Li is additionally co-substituted for Mg, S_ab remains unchanged but S_c increases substantially. The Li substitution donates holes into the π band rather than into the σ band and in this way modifies the π band properties, including the possible increase in the intraband scattering.

Interplay Between Spin Density Wave and Superconductivity in `122' Iron Pnictides: ^{57}Fe Mössbauer Study

100%

Błachowski A., Ruebenbauer K., Żukrowski J., Bukowski Z., Matusiak M., Karpinski J.

Acta Physica Polonica A

2012

vol. 121

issue 4

726-729

Iron-based superconductors Ba_{0.7}Rb_{0.3}Fe_{2}As_{2} and CaFe_{1.92}Co_{0.08}As_{2} of the `122' family have been investigated by means of the 14.41-keV Mössbauer transition in ^{57}Fe versus temperature ranging from the room temperature till 4.2 K. A comparison is made with the previously investigated parent compounds BaFe_{2}As_{2} and CaFe_{2}As_{2}. It has been found that Mössbauer spectra of these superconductors are composed of the magnetically split component due to development of spin density wave and non-magnetic component surviving even at lowest temperatures. The latter component is responsible for superconductivity. Hence, the superconductivity occurs in the part of the sample despite the sample is single phase. This phenomenon is caused by the slight variation of the dopant concentration across the sample (crystal).

Refine search results

2 Acta Physica Polonica A

1 2012

1 2008

2 Karpinski J.

1 Bukowski Z.

1 Błachowski A.

1 Katrych S.

1 Matusiak M.

1 Oganisian K.

1 Rogacki K.

1 Ruebenbauer K.

1 Sulkowski C.

1 Zhigadlo N.

1 Żukrowski J.

Search results

Thermoelectric Power of MgB_2 Single Crystals Doped with Holes and Electrons

Interplay Between Spin Density Wave and Superconductivity in `122' Iron Pnictides: ^{57}Fe Mössbauer Study