Half-Metallic Transport and Spin-Polarized Tunneling through the van der Waals Ferromagnet FeGeTe.

We examine the coherent spin-dependent transport properties of the van der Waals (vdW) ferromagnet FeGeTe using density functional theory combined with the nonequilibrium Green's function method. Our findings reveal that the conductance perpendicular to the layers is half-metallic, meaning that it is almost entirely spin-polarized. This property persists from the bulk to a single layer, even under significant bias voltages and with spin-orbit coupling.

Understanding complex multiple sublattice magnetism in double double perovskites.

Understanding magnetism in multiple magnetic sublattice system, driven by the interplay of varied nature of magnetic exchanges, is on one hand challenging and on other hand intriguing. Motivated by the recent synthesis of AA[Formula: see text]BB[Formula: see text]O[Formula: see text] double double perovskites with multiple magnetic ions both at A- and B-sites, we investigate the mechanism of magnetic behavior in these interesting class of compounds. We find that the magnetism in such multiple sublattice compounds is governed by the interplay and delicate balance between two distinct mechanisms, (a) kinetic energy-driven multiple sublattice double exchange mechanism and (b) the conventional super-exchange mechanism.

The Critical Role of Stereochemically Active Lone Pair in Introducing High Temperature Ferroelectricity.

In this paper, a comparative structural, dielectric, and magnetic study of two langasite compounds BaTeCoPO (absence of lone pair) and PbTeCoPO (Pb 6s lone pair) have been carried out to precisely explore the development of room temperature spontaneous polarization in the presence of a stereochemically active lone pair. In the case of PbTeCoPO, mixing of both Pb 6s with Pb 6p and O 2p helps the lone pair to be stereochemically active. This stereochemically active lone pair brings a large structural distortion within the unit cell and creates a polar geometry, while the BaTeCoPO compound remains in a nonpolar structure due to the absence of any such effect.