A magnetic phase diagram for nanoscale epitaxial BiFeO3 films
- Univ. of New South Wales, Sydney, NSW (Australia). School of Materials Science and Engineering; OSTI
- Normandie Univ., UNIROUEN, INSA Rouen, CNRS, GPM, Rouen (France)
- Univ. of Arkansas, Fayetteville, AR (United States). Dept. of Physics. Inst. for Nanoscience and Engineering; Soochow Univ., Suzhou (China). School of Physical Science and Technology
- Univ. of New South Wales, Sydney, NSW (Australia). School of Materials Science and Engineering
- CNRS, Thales, Univ. Paris-Sud, Univ. Paris-Saclay, Palaiseau (France). Unité Mixte de Physique
- Johannes Gutenberg-Univ. Mainz (Germany). Inst. of Physics. INSPIRE Group
- Univ. Paris Diderot (France). Lab. Matériaux et Phénomènes Quantiques (UMR 7162 CNRS)
- Univ. Paris-Saclay, Gif-sur-Yvette (France). Lab. Structures, Propriétés et Modélisation des Solides. CentraleSupélec. CNRS-UMR8580
- Univ. of Arkansas, Fayetteville, AR (United States). Dept. of Physics. Inst. for Nanoscience and Engineering
BiFeO3 thin films have attracted considerable attention by virtue of their potential application in low-energy spintronic and magnonic devices. BiFeO3 possesses an intricate magnetic structure, characterized by a spin cycloid with period ~62 nm that governs the functional magnonic response, and which can be modulated or even destroyed by strain, magnetic and electric fields, or chemical doping. The literature on (110)-oriented BiFeO3 films is not explicit in defining the conditions under which this cycloid persists, as its presence depends on synthesis method and thin-film boundary conditions, especially in the sub-100 nm thickness regime. This report aims to end “trial and error” approaches in determining the conditions under which this cycloid and its associated functional magnonic response exist. We show that in specific crystallographic orientations of epitaxial BiFeO3, an unexplored strain parameter—the distortion in the ab plane of the monoclinic unit cell—significantly influences the spin structure. Combining Mössbauer spectroscopy and low-energy Raman spectroscopy with first-principles-based effective Hamiltonian calculations, we show that both average strain and this distortion destroy the cycloid. For films grown on (110)-oriented SrTiO3 substrates, if the BiFeO3 lattice parameters a and b differ by more than about 1.2%, the cycloid is destabilized, resulting in a pseudocollinear magnetic order ground state. We are thereby able to construct a phase diagram of the spin structure for nanoscale epitaxial BiFeO3 films, which aims to resolve long-standing literature inconsistencies and provide powerful guidelines for the design of future magnonic and spintronic devices.
- Research Organization:
- Univ. of Arkansas, Fayetteville, AR (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0002220
- OSTI ID:
- 1801556
- Alternate ID(s):
- OSTI ID: 1574061
- Journal Information:
- Applied Physics Reviews, Journal Name: Applied Physics Reviews Journal Issue: 4 Vol. 6; ISSN 1931-9401
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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