High spin polarization in the ferromagnetic filled skutterudites KFe4Sb12 and NaFe4Sb12

Abstract

The spin polarization of ferromagnetic alkali-metal iron antimonides KFe4Sb12 and NaFe4Sb12 is studied by point-contact Andreev reflection using superconducting Nb and Pb tips. From these measurements an intrinsic transport spin polarization Pt of 67% and 60% for the K and Na compound, respectively, is inferred which establishes these materials as a new class of highly spin polarized ferromagnets. The results are in accord with band structure calculations within the local spin density approximation (LSDA) that predict nearly 100% spin polarization in the density of states. We discuss the impact of calculated Fermi velocities and spin fluctuations on Pt.

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• Iron-Based Heavy Quasiparticles in SrFe${}_4$Sb${}_{12}$: An Infrared Spectroscopic Study
• A modular point contact spectroscopy probe for sub-Kelvin applications
• High spin-polarization in the low Curie temperature complex itinerant ferromagnet EuTi${}_{1-x}$Nb${}_x$O${}_3$
• Exploring unconventional superconductivity in PdTe via Point Contact Spectroscopy