Exploring Magnetoelectric Properties in SrRuO3/BaTiO3/SrTiO3/SrRuO3 Interfaces

Listen up, young minds! Scientists have been really interested in a special type of junction called all-oxide ferroelectric tunnel junctions. These junctions are made of materials like SrRuO3, BaTiO3, and SrTiO3, and they're great for high-density, low-power applications. Why? Because they can be fine-tuned and scaled down to atomic sizes, making them super flexible. Scientists used some complex calculations and something called NEGFs formalism to study how electrons behave in these magnetoelectric interfaces. They looked at interfaces with different amounts of SrTiO3, specifically 0, 2, or 4 unit cells. They found some cool stuff!For example, the direction of the polarization can change whether the junction acts like a Schottky barrier or an Ohmic contact. This depends on the number of SrTiO3 cells. Interestingly, the junctions with 2 or 4 SrTiO3 cells always act like Schottky barriers. They also checked out something called tunnel electroresistance and tunnel magnetoresistance at different temperatures, 0 and 300 Kelvin. They discovered that the junction with 2 SrTiO3 cells showed the most response to magnetoelectric effects. This system even has those giant effects happening together! But here's a puzzle: Even though there's significant ferromagnetism in SrRuO3, the magnetoelectric coupling at the interface isn't strong enough to totally control the tunnel magnetoresistance by switching the polarization.