magnetic properties and materials

Thickness-Tunable Zoology of Magnetic Spin Txtures Observed in Fe5GeTe2

by NANOSENSORS
27 February 202527 February 2025
Science & Technology

Figure 4. from Ajesh K. Gopi et al. 2024: (a–e) MFM images of a bulk crystal with thickness ∼170 μm recorded at 100 K in the presence of an external field. Numbers in the upper right corner of each image show the corresponding field strength. (f) Magnified images of two selected regions (2 μm × 2 μm) in (e) showing two distinct magnetic contrasts. (g) Schematic representation showing the sample hosting different magnetic textures that result in different magnetic contrasts in MFM measurements. NANOSENSORSTM SSS-MFMR, a magnetic AFM probe with an AFM tip radius of curvature < 15 nm was used for all measurements.

The family of two-dimensional (2D) van der Waals (vdW) materials provides a playground for tuning structural and magnetic interactions to create a wide variety of… Read More »Thickness-Tunable Zoology of Magnetic Spin Txtures Observed in Fe5GeTe2

Energy dissipation on magic angle twisted bilayer graphene

by NANOSENSORS
11 December 202411 December 2024
Science & Technology

Fig. 1 a and b from Alexina Ollier et al 2023 “Energy dissipation on magic angle twisted bilayer graphene”: Pendulum atomic force microscope (p-AFM) tip oscillating on top of a twisted bilayer graphene (tBLG) device is measuring energy loss. a schematics of the measured device. The sample is composed of a p-doped silicon backgate (dark gray), followed by a 300 nm thick silicon dioxide layer (violet) and 10 nm hexagonal boron nitride (hBN, light blue). From the top tBLG is encapsulated with 10nm hBN film. b p-AFM image of the tBLG device, the white dotted rectangle is the device with a size of 4.1 μm × 5.8 μm. NANOSENSORS AdvancedTEC ATEC-CONT tip-view AFM probes were used.

Traditional Joule dissipation omnipresent in today’s electronic devices is well understood while the energy loss of the strongly interacting electron systems remains largely unexplored. Twisted… Read More »Energy dissipation on magic angle twisted bilayer graphene

Room-temperature sub-100 nm Néel-type skyrmions in non-stoichiometric van der Waals ferromagnet Fe3-xGaTe2 with ultrafast laser writability

Fig. 4 from Zefang Li et al. (2024) “Room-temperature sub-100 nm Néel-type skyrmions in non-stoichiometric van der Waals ferromagnet Fe3-xGaTe2 with ultrafast laser writability”: Thickness-tunable skyrmions imaged by MFM. a Typical MFM images of RT skyrmions taken at different thicknesses and external magnetic fields. In these images, bright contrast in the images corresponds to spin down, while dark contrast corresponds to spin up relative to the sample normal direction. The inset shows the schematic for the MFM experiment with magnetic field perpendicular to the sample plane. b RT skyrmion diameter dsk versus sample thickness t at zero field. c Comparison for diameter dsk of field-free skyrmions and temperature T for various 2D vdW materials with a thickness around 100 nm, including Cr1+xTe234, Fe3-xGeTe255, Fe5GeTe224, (Fe0.5Co0.5)5GeTe231, and Fe2.84±0.05GaTe2 in this work. Error bars represent the standard error of skyrmion sizes averaged at various temperature. d Thickness and magnetic field dependence of RT skyrmion phase diagram. The color indicates the skyrmion density ρsk. The black dashed line shows the boundary between skyrmion and ferromagnetic phase. The magnetic force microscopy (MFM) measurements were performed with a commercially available Atomic Force Microscope and NANOSENSORSTM low-moment magnetic AFM tips PPP-LM-MFMR. The MFM measurements were carried out in an environment continuously flushed with argon gas to ensure effective protection.

The small size and magnetoelectronic properties of magnetic skyrmions make them promising candidates as data carriers for future high-density and fast-speed data storage, quantum and… Read More »Room-temperature sub-100 nm Néel-type skyrmions in non-stoichiometric van der Waals ferromagnet Fe3-xGaTe2 with ultrafast laser writability

Domain-wall magnetoelectric coupling in multiferroic hexagonal YbFeO3 films

Supplementary Figure.S15 from “Domain-wall magnetoelectric coupling in multiferroic hexagonal YbFeO3 films” by Xin Li et al.: (a) MFM images of h-YbFeO3(001)/ YSZ(111), which were measured in the phase-lock mode 100 nm above the surface with a 3×3 m scan area. The gray scale of the images corresponds to the frequency shift, whose full scale is 1 Hz. The arrows indicate the sequence of the applied magnetic field along the c axis of h-YbFeO3 films. (b) Surface topography of h-YbFeO3 films measured by AFM with a 75 nm full grey scale. (c) Magnetic-field dependence of the roughness of the MFM images calculated using the central part of the images in (a). (d) The distribution of magnetic domain sizes extracted from the central part of the images in (a) with reducing magnetic field. All measurements were taken at 12 K. NANOSENSORS PPP-MFMR AFM probes with magnetic coating were used.

Electrical modulation of magnetic states in single-phase multiferroic materials, using domain-wall magnetoelectric (ME) coupling, can be enhanced substantially by controlling the population density of the… Read More »Domain-wall magnetoelectric coupling in multiferroic hexagonal YbFeO3 films

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

by NANOSENSORS
20 September 202015 March 2023
Science & Technology

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.

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,… Read More »Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host

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

by NANOSENSORS
24 August 202015 March 2023
Science & Technology

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

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

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

by NANOSENSORS
13 May 202015 March 2023
Science & Technology

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.

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… Read More »Observation of a gel of quantum vortices in a superconductor at very low magnetic fields