Magnetic phase diagram of an Fe monolayer on W(110) and Ta(110) surfaces based on ab initio calculations

TL;DR

This study uses ab initio calculations to explore the magnetic phase diagram of an Fe monolayer on W(110) and Ta(110) surfaces, revealing various ground states and phase transitions influenced by layer relaxation.

Contribution

It provides a detailed ab initio analysis of magnetic states and phase transitions in Fe monolayers on W(110) and Ta(110), including the effects of relaxation and temperature.

Findings

Reorientation of easy axis in Fe/W(110) with relaxation.

Switching from ferromagnetic to spin spiral states in Fe/Ta(110).

Temperature-induced phase transitions between magnetic states.

Abstract

We present detailed investigations of the magnetic properties of an Fe monolayer on W and Ta (110) surfaces based on the ab initio screened Korringa-Kohn-Rostoker method. By calculating tensorial exchange coupling coefficients, the ground states of the systems are determined using atomistic spin dynamics simulations. Different types of ground states are found in the systems as a function of relaxation of the Fe layer. In case of W(110) substrate this is reflected in a reorientation of the easy axis from in-plane to out-of-plane. For Ta(110) a switching appears from the ferromagnetic state to a cycloidal spin spiral state, then to another spin spiral state with a larger wave vector and, for large relaxations, a rotation of the normal vector of the spin spiral is found. Classical Monte Carlo simulations indicate temperature-induced transitions between the different magnetic phases observed in the Fe/Ta(110) system. These phase transitions are analyzed both quantitatively and qualitatively by finite-temperature spin wave theory.