[Paper Review] Magnetoelectricity in Multiferroics: a Theoretical Perspective

Shuai Dong, Hongjun Xiang+1 more|arXiv (Cornell University)|Feb 5, 2019

Multiferroics and related materialsMaterials Science114 references3 citations

TL;DR

This theoretical review explores the fundamental mechanisms underlying magnetoelectric coupling in multiferroic materials, focusing on single-phase multiferroics and magnetoelectric heterostructures. It identifies key mechanisms such as spin-driven polarization and exchange striction, and discusses recent advances in understanding emergent magnetoelectric effects, providing a comprehensive framework for future materials design.

ABSTRACT

The key physical property of multiferroic materials is the existence of a coupling between magnetism and polarization, i.e. magnetoelectricity. The origin and manifestations of magnetoelectricity can be very different in the available plethora of multiferroic systems, with multiple possible mechanisms hidden behind the phenomena. In this Review, we describe the fundamental physics that causes magnetoelectricity from a theoretical viewpoint. The present review will focus on the main stream physical mechanisms in both single phase multiferroics and magnetoelectric heterostructures. The most recent tendencies addressing possible new magnetoelectric mechanisms will also be briefly outlined.

Motivation & Objective

• To systematically analyze the theoretical origins of magnetoelectric coupling in multiferroic materials.
• To distinguish and explain the dominant physical mechanisms behind magnetoelectric effects in single-phase multiferroics and heterostructures.
• To summarize recent theoretical developments and identify emerging mechanisms in multiferroic systems.
• To provide a comprehensive theoretical foundation for guiding the discovery and engineering of new multiferroic materials.

Proposed method

• Theoretical analysis based on first-principles calculations and symmetry considerations to identify magnetoelectric coupling mechanisms.
• Use of group theory and spin-lattice coupling models to classify possible magnetoelectric responses.
• Examination of spin-driven ferroelectricity via Dzyaloshinskii-Moriya interactions and inverse Dzyaloshinskii-Moriya effects.
• Investigation of exchange striction and orbital ordering as sources of polarization in magnetic lattices.
• Analysis of interfacial magnetoelectric effects in heterostructures using effective Hamiltonian models.
• Review of recent theoretical proposals for novel magnetoelectric mechanisms beyond conventional mechanisms.

Experimental results

Research questions

• RQ1 What are the primary microscopic mechanisms responsible for magnetoelectric coupling in multiferroic materials?
• RQ2 How do spin-lattice and spin-orbit interactions contribute to emergent electric polarization in magnetic systems?
• RQ3 What role do symmetry constraints and crystal structure play in enabling magnetoelectric effects?
• RQ4 How do interfacial effects in heterostructures enhance or modify magnetoelectric coupling?
• RQ5 What new theoretical mechanisms are emerging in recent studies of multiferroics?

Key findings

• Spin-driven ferroelectricity via Dzyaloshinskii-Moriya interactions is a dominant mechanism in certain multiferroics, particularly in hexagonal manganites.
• Exchange striction and orbital ordering can induce significant polarization in magnetic lattices, especially in transition metal oxides.
• Theoretical models confirm that interfacial magnetoelectric coupling in heterostructures can be enhanced by interfacial spin-orbit coupling and broken inversion symmetry.
• Symmetry analysis reveals that only specific magnetic point groups allow for linear magnetoelectric effects, constraining possible material realizations.
• Recent theoretical work suggests that non-collinear spin textures and chiral spin liquids may host unconventional magnetoelectric responses.
• The review identifies persistent challenges in predicting and engineering large magnetoelectric responses, particularly in complex oxides with competing interactions.