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Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3.

Dixit H, Lee JH, Krogel JT, Okamoto S, Cooper VR - Sci Rep (2015)

Bottom Line: Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption.However, the degenerate nature of the easy spin axis in the (111) plane presents roadblocks for real world applications.We demonstrate that the antiferromagnetic moment vector can be stabilized along unique crystallographic directions ([110] and [-110]) under compressive and tensile strains.

View Article: PubMed Central - PubMed

Affiliation: Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830, USA.

ABSTRACT
Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption. However, the degenerate nature of the easy spin axis in the (111) plane presents roadblocks for real world applications. Here, we explore the stabilization and switchability of the weak ferromagnetic moments under applied epitaxial strain using a combination of first-principles calculations and group-theoretic analyses. We demonstrate that the antiferromagnetic moment vector can be stabilized along unique crystallographic directions ([110] and [-110]) under compressive and tensile strains. A direct coupling between the anisotropic antiferrodistortive rotations and the Dzyaloshinskii-Moria interactions drives the stabilization of the weak ferromagnetism. Furthermore, energetically competing C- and G-type magnetic orderings are observed at high compressive strains, suggesting that it may be possible to switch the weak ferromagnetism "on" and "off" under the application of strain. These findings emphasize the importance of strain and antiferrodistortive rotations as routes to enhancing induced weak ferromagnetism in multiferroic oxides.

No MeSH data available.


Related in: MedlinePlus

Variation in the in-plane (x-y) and out-plane (z) components of the (a) polarisation (P) and (b) antiferrodistortive (AFD) rotations under applied epitaxial strain.
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f2: Variation in the in-plane (x-y) and out-plane (z) components of the (a) polarisation (P) and (b) antiferrodistortive (AFD) rotations under applied epitaxial strain.

Mentions: We now discuss the changes in the electric polarisation direction and the AFD rotations with respect to applied epitaxial strain. Under applied compressive strains, the polarisation vector rotates along the (–110) plane towards the [001] direction (decreasing θ, while φ remains constant), away from the R3c [111]. On the other hand, for tensile strains the polarisation vector rotates towards the [110] direction along the (–110) plane. The rotation of the polarisation vector is strongly correlated with the FeO6 octahedral rotation patterns. Figure 2 summarises the changes in the x, y and z-components of the polarisation vector and the antiferrodistortive (AFD) rotations as a function of applied epitaxial strain. For the rhombohedral ground state, the calculated out-of-phase rotation of the FeO6 octahedra about the [111] direction is 13.2°, which is in good agreement with the experimentally measured value of 12.8°25. For compressive strains, we observe that the in-plane (x and y) components of the AFD rotations increase from 13.2° to 14°, while the z-component, rapidly decreases from 13.2° to 11.5°. For tensile strains, the x- and y-components of the AFD rotations rapidly decrease from 13.2° to 11° while the z-component remains nearly constant.


Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3.

Dixit H, Lee JH, Krogel JT, Okamoto S, Cooper VR - Sci Rep (2015)

Variation in the in-plane (x-y) and out-plane (z) components of the (a) polarisation (P) and (b) antiferrodistortive (AFD) rotations under applied epitaxial strain.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526888&req=5

f2: Variation in the in-plane (x-y) and out-plane (z) components of the (a) polarisation (P) and (b) antiferrodistortive (AFD) rotations under applied epitaxial strain.
Mentions: We now discuss the changes in the electric polarisation direction and the AFD rotations with respect to applied epitaxial strain. Under applied compressive strains, the polarisation vector rotates along the (–110) plane towards the [001] direction (decreasing θ, while φ remains constant), away from the R3c [111]. On the other hand, for tensile strains the polarisation vector rotates towards the [110] direction along the (–110) plane. The rotation of the polarisation vector is strongly correlated with the FeO6 octahedral rotation patterns. Figure 2 summarises the changes in the x, y and z-components of the polarisation vector and the antiferrodistortive (AFD) rotations as a function of applied epitaxial strain. For the rhombohedral ground state, the calculated out-of-phase rotation of the FeO6 octahedra about the [111] direction is 13.2°, which is in good agreement with the experimentally measured value of 12.8°25. For compressive strains, we observe that the in-plane (x and y) components of the AFD rotations increase from 13.2° to 14°, while the z-component, rapidly decreases from 13.2° to 11.5°. For tensile strains, the x- and y-components of the AFD rotations rapidly decrease from 13.2° to 11° while the z-component remains nearly constant.

Bottom Line: Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption.However, the degenerate nature of the easy spin axis in the (111) plane presents roadblocks for real world applications.We demonstrate that the antiferromagnetic moment vector can be stabilized along unique crystallographic directions ([110] and [-110]) under compressive and tensile strains.

View Article: PubMed Central - PubMed

Affiliation: Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830, USA.

ABSTRACT
Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption. However, the degenerate nature of the easy spin axis in the (111) plane presents roadblocks for real world applications. Here, we explore the stabilization and switchability of the weak ferromagnetic moments under applied epitaxial strain using a combination of first-principles calculations and group-theoretic analyses. We demonstrate that the antiferromagnetic moment vector can be stabilized along unique crystallographic directions ([110] and [-110]) under compressive and tensile strains. A direct coupling between the anisotropic antiferrodistortive rotations and the Dzyaloshinskii-Moria interactions drives the stabilization of the weak ferromagnetism. Furthermore, energetically competing C- and G-type magnetic orderings are observed at high compressive strains, suggesting that it may be possible to switch the weak ferromagnetism "on" and "off" under the application of strain. These findings emphasize the importance of strain and antiferrodistortive rotations as routes to enhancing induced weak ferromagnetism in multiferroic oxides.

No MeSH data available.


Related in: MedlinePlus