Slater-Pauling Behavior of the Half-Ferromagnetic Full-Heusler Alloys

TL;DR

This study investigates the magnetic and electronic properties of full-Heusler alloys, revealing a Slater-Pauling rule governing their magnetic moments and discussing their half-metallic behavior with small minority gaps.

Contribution

It demonstrates that full-Heusler alloys follow a specific Slater-Pauling rule for magnetic moments and explains the electronic structure reasons behind this behavior.

Findings

Many full-Heusler alloys exhibit half-metallicity.

The total magnetic moment follows M_t=Z_t-24 rule.

The minority band contains exactly 12 electrons, explained by group theory.

Abstract

Using the full-potential screened Korringa-Kohn-Rostoker method we study the full-Heusler alloys based on Co, Fe, Rh and Ru. We show that many of these compounds show a half-metallic behavior, however in contrast to the half-Heusler alloys the energy gap in the minority band is extremely small. These full-Heusler compounds show a Slater-Pauling behavior and the total spin-magnetic moment per unit cell (M_t) scales with the total number of valence electrons (Z_t) following the rule: M_t=Z_t-24. We explain why the spin-down band contains exactly 12 electrons using arguments based on the group theory and show that this rule holds also for compounds with less than 24 valence electrons. Finally we discuss the deviations from this rule and the differences compared to the half-Heusler alloys.