Jeanne Colbois PRO
Physicist @ CNRS. Here you find slides for *some* of my presentations, as well as visual abstracts for recent publications.
Artificial out-of-plane Ising antiferromagnet
on the kagome lattice
with very small farther-neighbor couplings
Jeanne Colbois¹, Kevin Hofhuis² ³, Zhaochu Luo² ³, Xueqiao Wang² ³, Aleš Hrabec ² ³ , Laura J. Heyderman² ³, and Frédéric Mila¹
(1) EPF Lausanne Institute of Physics, (2) ETH Zürich Department of Materials,
(3) Paul Scherrer Institute Laboratory for Multiscale Materials experiments
Switzerland
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Out-of-plane systems on kagome
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2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Out-of-plane systems on kagome
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2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Out-of-plane systems on kagome
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Zhang et al., Phys. Rev. Lett. 109, (2012)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Essential role of farther-neighbor couplings
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H = \sum_{(i,j)} J_{i,j} \sigma_i \sigma_j \\
J_{i,j} \propto 1/|r_i -r_j|^3
Chioar et al., Phys. Rev. B 90, (2014)
Non-universality: farther-neighbors couplings play a role in the selection of the correlations
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Chirally coupled nanomagnets
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Luo et al., Science 363, 1435-1439 (2019)
Context
Chirally coupled nanomagnets
Pt(6 nm)/Co(1.6 nm)/Al(2 nm)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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Dzyaloshinskii-Moryia interaction
- Here : interfacial DMI
Context
Chirally coupled nanomagnets
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Luo et al., Science 363, 1435-1439 (2019)
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The magnetic anisotropy is controlled by the oxidization of the Co/Al interface
(the in-plane regions are protected and the out-of-plane regions are oxidized)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Chirally coupled nanomagnets
Luo et al., Science 363, 1435-1439 (2019)
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The magnetic anisotropy is controlled by the oxidization of the Co/Al interface
(the in-plane regions are protected and the out-of-plane regions are oxidized)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Chirally coupled nanomagnets
Luo et al., Science 363, 1435-1439 (2019)
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Result : an effective antiferromagnetic nearest-neighbour coupling for the out-of-plane (OOP) regions
(MFM image)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Chirally coupled nanomagnets
Luo et al., Science 363, 1435-1439 (2019)
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2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Chirally coupled nanomagnets
Luo et al., Science 363, 1435-1439 (2019)
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
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2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Questions
1. What would be a good effective model for these chirally coupled systems?
2. Should we expect farther-neighbor couplings to still play a role?
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
SEM
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2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
SEM
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OOP
IP
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
SEM
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- Effective model for the OOP spins on a 5-sites island
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
SEM
- Effective model for the OOP spins on a 5-sites island
- Systematic micromagnetic simulations assuming that the IP region takes the configuration of minimal energy
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
5
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
- Effective model for the OOP spins on a 5-sites island
- Systematic micromagnetic simulations assuming that the IP region takes the configuration of minimal energy
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
- Effective model for the OOP spins on a 5-sites island
- Systematic micromagnetic simulations assuming that the IP region takes the configuration of minimal energy
\frac{J_1}{J_1^{\text{dip}}} \cong 8.7 \pm 0.1
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
- Effective model for the OOP spins on a 5-sites island
- Systematic micromagnetic simulations assuming that the IP region takes the configuration of minimal energy
\frac{J_1}{J_1^{\text{dip}}} \cong 8.7 \pm 0.1
\frac{J_2}{J_2^{\text{dip}}} \cong 1.67 \pm 0.01
\frac{J_{3||}}{J_{3||}^{\text{dip}}} \cong 1.12 \pm 0.01
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
- Effective model for the OOP spins on a 5-sites island
- Systematic micromagnetic simulations assuming that the IP region takes the configuration of minimal energy
\frac{J_1}{J_1^{\text{dip}}} \cong 8.7 \pm 0.1
\frac{J_2}{J_2^{\text{dip}}} \cong 1.67 \pm 0.01
\frac{J_{3||}}{J_{3||}^{\text{dip}}} \cong 1.12 \pm 0.01
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Effective model
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Farther-neighbor to nearest-neighbor couplings ratios are much smaller than in the dipolar case!
(J2/J1 ~ 2%)
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
- An overall up magnetization
- 10% to 15% of ferromagnetic triangles
- Short-range spin-spin correlations
20 samples
MFM
AFM
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
- 1. An overall up magnetization (0.19)
- 2.10% to 15% of ferromagnetic triangles
- 3. Short-range spin-spin correlations
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
- 1. An overall up magnetization (0.19)
- 2.10% to 15% of ferromagnetic triangles
- 3. Short-range spin-spin correlations
7
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
- 1. An overall up magnetization (0.19)
- 2.10% to 15% of ferromagnetic triangles
- 3. Short-range spin-spin correlations
8
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
c_k = \langle \sigma_i \sigma_j \rangle_k - \langle \sigma_i \rangle \langle \sigma_j \rangle
- 1. An overall up magnetization (0.19)
- 2.10% to 15% of ferromagnetic triangles
- 3. Short-range spin-spin correlations
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
c_k = \langle \sigma_i \sigma_j \rangle_k - \langle \sigma_i \rangle \langle \sigma_j \rangle
|c_1| > c_{3||} \gtrsim 2c_2
- 1. An overall up magnetization (0.19)
- 2.10% to 15% of ferromagnetic triangles
- 3. Short-range spin-spin correlations
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
c_k = \langle \sigma_i \sigma_j \rangle_k - \langle \sigma_i \rangle \langle \sigma_j \rangle
|c_1| > c_{3||} \gtrsim 2c_2
1. The effective model does not fully explain all three results at once.
- 1. An overall up magnetization (0.19)
- 2.10% to 15% of ferromagnetic triangles
- 3. Short-range spin-spin correlations
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Experimental results
c_k = \langle \sigma_i \sigma_j \rangle_k - \langle \sigma_i \rangle \langle \sigma_j \rangle
|c_1| > c_{3||} \gtrsim 2c_2
1. The effective model does not fully explain all three results at once.
2. It does tell us about the role of farther-neighbor couplings.
- 1. An overall up magnetization (0.19)
- 2.10% to 15% of ferromagnetic triangles
- 3. Short-range spin-spin correlations
Discussion of the numerical results
Nearest-neighbor model
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
See also: Sejman, Zukovic, Acta Phys. Pol. A 137, 622 (2020)
Loh, Yao, Carlson, Phys. Rev. B 77, 134402 (2008)
Li et al., Phys. Rev. B 82, 134434 (2010)
Zero field
Barry and Khatun, Int. J. Mod. Phys. B 11, 93 (1997)
Discussion of the numerical results
Nearest-neighbor model
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
See also: Sejman, Zukovic, Acta Phys. Pol. A 137, 622 (2020)
Loh, Yao, Carlson, Phys. Rev. B 77, 134402 (2008)
Li et al., Phys. Rev. B 82, 134434 (2010)
Zero field
~Effective temperature
Discussion of the numerical results
Nearest-neighbor model
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
See also: Sejman, Zukovic, Acta Phys. Pol. A 137, 622 (2020)
Loh, Yao, Carlson, Phys. Rev. B 77, 134402 (2008)
Li et al., Phys. Rev. B 82, 134434 (2010)
Zero field
Inversion in the order of the correlations between theory and experiment
~Effective temperature
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Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
See also: Takagi, Mekata, J.Phys. Soc. Jpn. 62, 3943 (1993)
Wills, Ballou, Lacroix, PRB 66, 144407 (2002)
Chern, Tchernyshyov, P. Trans. R. Soc. A 370, 5718 (2012)
Hamp , Castelnovo, Moessner, PRB 98 (2018)
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Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
See also: Takagi, Mekata, J.Phys. Soc. Jpn. 62, 3943 (1993)
Wills, Ballou, Lacroix, PRB 66, 144407 (2002)
Chern, Tchernyshyov, P. Trans. R. Soc. A 370, 5718 (2012)
Hamp , Castelnovo, Moessner, PRB 98 (2018)
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Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Partial lifting of the g.s. degeneracy
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
See also: Takagi, Mekata, J.Phys. Soc. Jpn. 62, 3943 (1993)
Wills, Ballou, Lacroix, PRB 66, 144407 (2002)
Chern, Tchernyshyov, P. Trans. R. Soc. A 370, 5718 (2012)
Hamp , Castelnovo, Moessner, PRB 98 (2018)
NN g.s. physics?
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Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
See also: Takagi, Mekata, J.Phys. Soc. Jpn. 62, 3943 (1993)
Wills, Ballou, Lacroix, PRB 66, 144407 (2002)
Chern, Tchernyshyov, P. Trans. R. Soc. A 370, 5718 (2012)
Hamp , Castelnovo, Moessner, PRB 98 (2018)
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
The spin-spin correlations are in the same order as in the experiment
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
Discussion of the numerical results
The role of next-nearest-neighbor couplings
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
If ,
the correlations at finite temperatures are significantly impacted.
J_2 \gtrsim 1 \% J_1
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Discussion of the numerical results
Teaser: the role of third-neighbor couplings and the field
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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Discussion of the numerical results
Teaser: the role of third-neighbor couplings and the field
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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J_1, J_2 \text{ model }
Discussion of the numerical results
Teaser: the role of third-neighbor couplings and the field
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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JC, Hofhuis, Luo et al., PRB 104, 024418 (2021)
The ground state still has a macroscopic degeneracy!
Discussion of the numerical results
Teaser: the role of third-neighbor couplings and the field
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
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Discussion of the numerical results
Teaser: the role of third-neighbor couplings and the field
More about this in
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
- Taking into account the magnetization and the first few correlations
- Finding three regions of interest
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2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Conclusions and outlook
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Conclusions and outlook
Chirally coupled nanomagnets
very strong NN interactions
Farther-neighbor couplings cannot be neglected
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2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Conclusions and outlook
Chirally coupled nanomagnets
very strong NN interactions
Farther-neighbor couplings cannot be neglected
- Long-range effective model?
- Role of disorder in the couplings?
- Observing the IP configurations to validate the effective model?
- Design with a triangular hole to reduce the farther-neighbor couplings?
Theory
Experiment
Acknowledgments
Kevin Hofhuis
Zhaochu Luo, Ales Hrabec, Xueqiao Wang, Laura Heyderman, Frédéric Mila
Thank you for your attention!
Bram Vanhecke, Laurens Vanderstraeten, Andrew Smerald, Frank Verstraete, Patrick Emonts, Mithilesh Nayak, Natalia Chepiga
And the Centro de ciencias de Benasque Pedro Pascual
Discussions:
Collaborators:
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
2022 Joint MMM-Intermag Conference - Jeanne Colbois - AOA-02
Context
Out-of-plane systems on kagome
H = \sum_{(i,j)} J_{i,j} \sigma_i \sigma_j \\
J_{i,j} \propto 1/|r_i -r_j|^3
Chioar et al., Phys. Rev. B 90, (2014)
Chioar et al., Phys. Rev. B 90, (2014)
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Artificial Out-of-Plane Ising Antiferromagnet on the Kagome Lattice with Very Small Farther-Neighbour Couplings
By Jeanne Colbois
Artificial Out-of-Plane Ising Antiferromagnet on the Kagome Lattice with Very Small Farther-Neighbour Couplings
Contributed talk at the Joint MMM -Intermag Conference 2022
