Tag Archives: Magnetic Force Microscopy probe

Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host

In the article “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” Korbinian Geirhos, Boris Gross, Bertalan G. Szigeti, Andrea Mehlin, Simon Philipp, Jonathan S. White, Robert Cubitt, Sebastian Widmann, Somnath Ghara, Peter Lunkenheimer, Vladimir Tsurkan, Erik Neuber, Dmytro Ivaneyko, Peter Milde, Lukas M. Eng, Andrey O. Leonov, Sándor Bordács, Martino Poggio and István Kézsmárki report a magnetic state in GaV4Se8 which emerges exclusively in samples with mesoscale polar domains and not in polar mono-domain crystals.*

It is manifested by a sharp anomaly in the magnetic susceptibility and the magnetic torque, distinct from other anomalies observed also in polar mono-domain samples upon transitions between the cycloidal, the Néel-type skyrmion lattice and the ferromagnetic states. *

The authors ascribe this additional transition to the transformation of distinct magnetic textures, confined to polar domain walls (DW), to the ferromagnetic (FM) state. The emergence of these DW-confined magnetic states is likely driven by the mismatch of different spin spirals, hosted by the adjacent domains. A clear anomaly in the magneto-current indicates that the DW-confined magnetic states also have strong contributions to the magnetoelectric response. *

The authors expect polar DWs to commonly host such confined magnetic edge states and, thus, offer a fertile ground to explore novel forms of magnetism. *

To characterize the polar domains and to estimate the density of DWs in GaV4Se8, K. Geirhos et al. combined several complementary scanning probe microscopy techniques, including non-contact atomic force microscopy ( nc-AFM ), scanning dissipation microscopy ( SDM ), and frequency-modulated Kelvin-probe force microscopy ( KPFM ). *

In attempt to observe spin cycloidal and Néel-type skyrmion textures within polar domains of GaV4Se8, only evidenced by small-angle neutron scattering measurements so far43, the authors of the article also carried out magnetic force microscopy (MFM) measurements. A second purpose of the MFM study was to explore possible magnetic states confined to the vicinity of DWs, as reported in GaV4S8. *

NANOSENSORS™ SSS-QMFMR high resolution magnetic AFM probes for ultra high vacuum conditions were used for the magnetic measurements with scanning probe microscopy. *

NANOSENSORS™ conductive wear-resistant Platinum Silicide AFM probes of the PtSi-FM type were used for all other measurements described in the article. *

Supplementary Figure 1 a – d from “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” by K. Geirhos et al:

Typical ferroelectric do-main pattern observed on the (001) cleaved GaV4Se8 crystal surface  atT=10  K.
a, The topography is characterized by stripes roughly parallel to the [110] axis and folds parallel to the [010]  axis. The latter originate in the differently oriented distortion of the ferroelastic domains. The color scale corresponds to the z-displacement of the tip.
b ,In the dissipation channel of the nc-AFM every second domain appears bright. For the non-magnetic tip the dissipation originates from electric interactions. The dissipated power is indicated by the color scale. Please have a look at the full article to view the full supplementary figure.
NANOSENSORS Platinum Silicide PtSi-FM AFM probes were used for the imaging.
Supplementary Figure 1 a – d from “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” by K. Geirhos et al:

Typical ferroelectric do-main pattern observed on the (001) cleaved GaV4Se8 crystal surface  atT=10  K.
a, The topography is characterized by stripes roughly parallel to the [110] axis and folds parallel to the [010]  axis. The latter originate in the differently oriented distortion of the ferroelastic domains. The color scale corresponds to the z-displacement of the tip.
b ,In the dissipation channel of the nc-AFM every second domain appears bright. For the non-magnetic tip the dissipation originates from electric interactions. The dissipated power is indicated by the color scale. Please have a look at the full article to view the full supplementary figure.

*Korbinian Geirhos, Boris Gross, Bertalan G. Szigeti, Andrea Mehlin, Simon Philipp, Jonathan S. White, Robert Cubitt, Sebastian Widmann, Somnath Ghara, Peter Lunkenheimer, Vladimir Tsurkan, Erik Neuber, Dmytro Ivaneyko, Peter Milde, Lukas M. Eng, Andrey O. Leonov, Sándor Bordács, Martino Poggio and István Kézsmárki
Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host
npj Quantum Materials volume 5, Article number: 44 (2020)
DOI: https://doi.org/10.1038/s41535-020-0247-z

Please follow this external link to read the full article: https://rdcu.be/b7lgW

Open Access The article “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” by Korbinian Geirhos, Boris Gross, Bertalan G. Szigeti, Andrea Mehlin, Simon Philipp, Jonathan S. White, Robert Cubitt, Sebastian Widmann, Somnath Ghara, Peter Lunkenheimer, Vladimir Tsurkan, Erik Neuber, Dmytro Ivaneyko, Peter Milde, Lukas M. Eng, Andrey O. Leonov, Sándor Bordács, Martino Poggio and István Kézsmárki is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Electric-field-driven non-volatile multi-state switching of individual skyrmions in a multiferroic heterostructure

Electrical manipulation of skyrmions attracts considerable attention for its rich physics and promising applications. To date, such a manipulation is realized mainly via spin-polarized current based on spin-transfer torque or spin–orbital torque effect.*

However, this scheme is energy consuming and may produce massive Joule heating. To reduce energy dissipation and risk of heightened temperatures of skyrmion-based devices, an effective solution is to use electric field instead of current as stimulus.*

In the article “Electric-field-driven non-volatile multi-state switching of individual skyrmions in a multiferroic heterostructure”, Yadong Wang, Lei Wang, Jing Xia, Zhengxun Lai, Guo Tian, Xichao Zhang, Zhipeng Hou, Xingsen Gao, Wenbo Mi, Chun Feng, Min Zeng, Guofu Zhou, Guanghua Yu, Guangheng Wu, Yan Zhou, Wenhong Wang, Xi-xiang Zhang and Junming Liu realize an electric-field manipulation of skyrmions in a nanostructured ferromagnetic/ferroelectrical heterostructure at room temperature via an inverse magneto-mechanical effect.*

Intriguingly, such a manipulation is non-volatile and exhibits a multistate feature. Numerical simulations indicate that the electric-field manipulation of skyrmions originates from strain-mediated modification of effective magnetic anisotropy and Dzyaloshinskii–Moriya interaction.*

The results presented in the article open a direction for constructing low-energy-dissipation, non-volatile, and multistate skyrmion-based spintronic devices.*

To minimize the influence of the magnetic field from the MFM tip on the magnetic domain structure during the magnetic force microscopy ( MFM ) measurements, NANOSENSORS™ PPP-LM-MFMR low moment magnetic AFM probes were used.*

These MFM probes are designed for magnetic force microscopy with reduced disturbance of the magnetic sample by the tip and enhanced lateral resolution compared to the standard PPP-MFMR probe. The distance between the tip and sample was maintained at a constant distance of 30 nm.*

Figure 2 from “Electric-field-driven non-volatile multi-state switching of individual skyrmions in a multiferroic heterostructure” by Yadong Wang et al.:
Electric-field-induced switching of individual skyrmion.
The transferred average strain εave and corresponding magnetic domain evolution processes in the d ~ 350 nm a [Pt/Co/Ta]12 and b [Pt/Co/Ta]8 nano-dots in a cycle of E ranging from +10 to −10 kV cm−1. Positive εave (red dots) represents tensile strain while negative εave (blue dots) represents compressive strain. μ0H represents the external magnetic field except that from the MFM tip and here μ0H is equal to be 0 mT. The inset of b illustrates the spin texture of the magnetic domain that is encompassed by the red box. The stripe domain enclosed by the black box shows the initial state of the magnetic domain evolution path. The gray dots represent the corresponding electric field for the MFM images. The MFM contrast represents the MFM tip resonant frequency shift (Δf). The scale bar represents 250 nm.

NANOSENSORS™ PPP-LM-MFMR low moment magnetic AFM probes were used
Figure 2 from “Electric-field-driven non-volatile multi-state switching of individual skyrmions in a multiferroic heterostructure” by Yadong Wang et al.:
Electric-field-induced switching of individual skyrmion.
The transferred average strain εave and corresponding magnetic domain evolution processes in the d ~ 350 nm a [Pt/Co/Ta]12 and b [Pt/Co/Ta]8 nano-dots in a cycle of E ranging from +10 to −10 kV cm−1. Positive εave (red dots) represents tensile strain while negative εave (blue dots) represents compressive strain. μ0H represents the external magnetic field except that from the MFM tip and here μ0H is equal to be 0 mT. The inset of b illustrates the spin texture of the magnetic domain that is encompassed by the red box. The stripe domain enclosed by the black box shows the initial state of the magnetic domain evolution path. The gray dots represent the corresponding electric field for the MFM images. The MFM contrast represents the MFM tip resonant frequency shift (Δf). The scale bar represents 250 nm.

*Yadong Wang, Lei Wang, Jing Xia, Zhengxun Lai, Guo Tian, Xichao Zhang, Zhipeng Hou, Xingsen Gao, Wenbo Mi, Chun Feng, Min Zeng, Guofu Zhou, Guanghua Yu, Guangheng Wu, Yan Zhou, Wenhong Wang, Xi-xiang Zhang and Junming Liu
Electric-field-driven non-volatile multi-state switching of individual skyrmions in a multiferroic heterostructure
Nature Communications volume 11, Article no. 3577 (2020)
DOI: https://doi.org/10.1038/s41467-020-17354-7

Please follow this external link to read the full article: https://rdcu.be/b6qpr

Open Access: The article “Electric-field-driven non-volatile multi-state switching of individual skyrmions in a multiferroic heterostructure” by Yadong Wang, Lei Wang, Jing Xia, Zhengxun Lai, Guo Tian, Xichao Zhang, Zhipeng Hou, Xingsen Gao, Wenbo Mi, Chun Feng, Min Zeng, Guofu Zhou, Guanghua Yu, Guangheng Wu, Yan Zhou, Wenhong Wang, Xi-xiang Zhang and Junming Liu is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Observation of a gel of quantum vortices in a superconductor at very low magnetic fields

A gel consists of a network of particles or molecules formed for example using the sol-gel process, by which a solution transforms into a porous solid. Particles or molecules in a gel are mainly organized on a scaffold that makes up a porous system. Quantized vortices in type-II superconductors mostly form spatially homogeneous ordered or amorphous solids.*

In the article “Observation of a gel of quantum vortices in a superconductor at very low magnetic fields” José Benito Llorens, Lior Embon, Alexandre Correa, Jesús David González, Edwin Herrera, Isabel Guillamón, Roberto F. Luccas, Jon Azpeitia, Federico J. Mompeán, Mar García-Hernández, Carmen Munuera, Jazmín Aragón Sánchez, Yanina Fasano, Milorad V. Milošević, Hermann Suderow and Yonathan Anahory present high-resolution imaging of the vortex lattice displaying dense vortex clusters separated by sparse or entirely vortex-free regions in β−Bi2Pd superconductor.*

The authors find that the intervortex distance diverges upon decreasing the magnetic field and that vortex lattice images follow a multifractal behavior. These properties, characteristic of gels, establish the presence of a novel vortex distribution, distinctly different from the well-studied disordered and glassy phases observed in high-temperature and conventional superconductors.*

The observed behavior is caused by a scaffold of one-dimensional structural defects with enhanced stress close to the defects. The vortex gel might often occur in type-II superconductors at low magnetic fields. Such vortex distributions should allow to considerably simplify control over vortex positions and manipulation of quantum vortex states.*

The results presented in the article show that vortices are nearly independent to each other at very low magnetic fields and that their position is locked to the defect structure in the sample. This suggests that vortices in this field range are also highly manipulable, much more than in usual hexagonal or disordered vortex lattices.

The magnetic force microscopy (MFM) measurements described in the article were performed in a commercial Low-Temperature  SPM equipment working in the 300–1.8  K temperature range using NANOSENSORS magnetic AFM probes of the type PPP-MFMR that were magnetized prior to the measurement by applying a magnetic field of 1500 G at 10 K.

figure 8 from “Observation of a gel of quantum vortices in a superconductor at very low magnetic fields” by José Benito Llorens et al.:
Behavior of the hexagonal vortex lattice as a function of temperature measured with MFM. In (a)–(c), the images are taken at 2.75,3.75, and 4.5 K, respectively at 300 G. The color scale represents the observed frequency shift. Scale bar is 1μm. Blue lines are the Delaunay triangulation of vortex positions. Blue and red points in (a) highlight vortices with seven and five nearest neighbors respectively. The dark arrow at the bottom highlights the position of the vertical line discussed in the text.
figure 8 from “Observation of a gel of quantum vortices in a superconductor at very low magnetic fields” by José Benito Llorens et al.:
Behavior of the hexagonal vortex lattice as a function of temperature measured with MFM. In (a)–(c), the images are taken at 2.75,3.75, and 4.5 K, respectively at 300 G. The color scale represents the observed frequency shift. Scale bar is 1μm. Blue lines are the Delaunay triangulation of vortex positions. Blue and red points in (a) highlight vortices with seven and five nearest neighbors respectively. The dark arrow at the bottom highlights the position of the vertical line discussed in the text.

*José Benito Llorens, Lior Embon, Alexandre Correa, Jesús David González, Edwin Herrera, Isabel Guillamón, Roberto F. Luccas, Jon Azpeitia, Federico J. Mompeán, Mar García-Hernández, Carmen Munuera, Jazmín Aragón Sánchez, Yanina Fasano, Milorad V. Milošević, Hermann Suderow, and Yonathan Anahory
Observation of a gel of quantum vortices in a superconductor at very low magnetic fields
Physical Review Research 2, 013329 (2020)
DOI:10.1103/PhysRevResearch.2.013329

Please follow this external link to read the full article: https://journals.aps.org/prresearch/pdf/10.1103/PhysRevResearch.2.013329

Open Access: The article “Observation of a gel of quantum vortices in a superconductor at very low magnetic fields” by José Benito Llorens, Lior Embon, Alexandre Correa, Jesús David González, Edwin Herrera, Isabel Guillamón, Roberto F. Luccas, Jon Azpeitia, Federico J. Mompeán, Mar García-Hernández, Carmen Munuera, Jazmín Aragón Sánchez, Yanina Fasano, Milorad V. Milošević, Hermann Suderow, and Yonathan Anahory is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.