Limits...
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

Calculated magnetic energy landscape for compressive (–) and tensile (+) strains of ±1, 3 and 5%. Bright (red) and dark (black) region correspond to hard and easy spin axes (also marked using dashed white arrows), respectively.Under both the compressive and tensile strains the antiferromagnetic vector (L) is stabilized along [110] and [–110] directions, respectively. Consequently, the induced weak ferromagnetism (Ms) is also stabilized along the [–110] and [001] directions under the compressive and tensile strains, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4526888&req=5

f3: Calculated magnetic energy landscape for compressive (–) and tensile (+) strains of ±1, 3 and 5%. Bright (red) and dark (black) region correspond to hard and easy spin axes (also marked using dashed white arrows), respectively.Under both the compressive and tensile strains the antiferromagnetic vector (L) is stabilized along [110] and [–110] directions, respectively. Consequently, the induced weak ferromagnetism (Ms) is also stabilized along the [–110] and [001] directions under the compressive and tensile strains, respectively.

Mentions: Next, we discuss the evolution of the induced weak ferromagnetism under applied epitaxial strain. Figure 3 shows the calculated magnetic energy landscapes under applied compressive and tensile strains. We observe that the wFM observed in the case of the rhombohedral ground state also persists for the tested strain values (±5%). In the tensile regime (the lower panel of Fig. 3), we observe that the degeneracy of the induced weak ferromagnetic moments is quickly lifted resulting in a preferred orientation along specific crystallographic directions. A careful analysis of the wFM shows that both the easy and hard spin axes now lie in the x-y plane and L is stabilized along the [–110] direction. The spontaneous magnetisation is found to linearly decrease from 0.033μB for the R3c structure to 0.026μB for the highest strained (+5%) phase.


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)

Calculated magnetic energy landscape for compressive (–) and tensile (+) strains of ±1, 3 and 5%. Bright (red) and dark (black) region correspond to hard and easy spin axes (also marked using dashed white arrows), respectively.Under both the compressive and tensile strains the antiferromagnetic vector (L) is stabilized along [110] and [–110] directions, respectively. Consequently, the induced weak ferromagnetism (Ms) is also stabilized along the [–110] and [001] directions under the compressive and tensile strains, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Calculated magnetic energy landscape for compressive (–) and tensile (+) strains of ±1, 3 and 5%. Bright (red) and dark (black) region correspond to hard and easy spin axes (also marked using dashed white arrows), respectively.Under both the compressive and tensile strains the antiferromagnetic vector (L) is stabilized along [110] and [–110] directions, respectively. Consequently, the induced weak ferromagnetism (Ms) is also stabilized along the [–110] and [001] directions under the compressive and tensile strains, respectively.
Mentions: Next, we discuss the evolution of the induced weak ferromagnetism under applied epitaxial strain. Figure 3 shows the calculated magnetic energy landscapes under applied compressive and tensile strains. We observe that the wFM observed in the case of the rhombohedral ground state also persists for the tested strain values (±5%). In the tensile regime (the lower panel of Fig. 3), we observe that the degeneracy of the induced weak ferromagnetic moments is quickly lifted resulting in a preferred orientation along specific crystallographic directions. A careful analysis of the wFM shows that both the easy and hard spin axes now lie in the x-y plane and L is stabilized along the [–110] direction. The spontaneous magnetisation is found to linearly decrease from 0.033μB for the R3c structure to 0.026μB for the highest strained (+5%) phase.

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