MFM imaging of a Skyrmion lattice made with attoDRY1000 with low temperature atomic force microscope

MFM imaging of a Skyrmion lattice

In collaboration with Jan Seidel from UNSW Sydney, A. Bauer & C. Pfleiderer, TU Munich we have successfully imaged the elusive Skyrmions and their magnetic field evolution in the attoDRY1000 cryostats using the attoAFM/MFM I. See what’s possible nowadays with our sophisticated commercial instruments!

This measurement was realized with the attoDRY1000, and the attoAFM I.


Scanning Tunneling Spectroscopy and Vortex Imaging on NbSe2 with attoAFM III   STM I at 315 mK made with attoLIQUID3000 and attoAFM III

Scanning Tunneling Spectroscopy and Vortex Imaging on NbSe2 with attoAFM III / STM I at 315 mK

Scanning Tunneling Spectroscopy (STS) is a useful tool to characterize material properties, especially on su­perconductors at ultra low temperatures. In a series of experiments STS measurements as well as vortex ima­ging on NbSe2 have been performed at a temperature of only 315 mK. The tests show excellent stability of the combined attoAFM/STM microscope setup as well as the possibility to apply stable voltages in the micro-Volt range.

This measurement was realized with the attoLIQUID3000, and the attoAFM III in Dry Dilution Refrigerator.


Tuning Fork based AFM measurements at cryogenic temperatures made with attoAFM III and attoLIQUID

Tuning Fork based AFM measurements at cryogenic temperatures

The attoAFM III is a tuning fork based setup for highly precise low temperature measurements. The non-optical design faciliates e.g. measurements on light-sensitive samples using conductive STM-type tips.
The distance feedback is done by detecting the tuning fork vibration using a Phase-Locked Loop (PLL) toge­ther with a feedback loop. The PLL tracks the resonance of the tuning fork, whereas the feedback loop keeps the z-distance in such way that the frequency shift (vs. the free oscillation) remains at a certain level.
The presented data was measured using uncapped, stacked InAs Quantum Dots in a GaAs matrix with an attoAFM III inside an attoLIQUID.

This measurement was realized with the attoLIQUID1000, and the attoAFM III.


attoAFM CFM in Toploading Insert attoAFM CFM oder CSFM  mK

attoAFM/CFM in Toploading Insert

The presented data was taken with a mk-compatible version of the attoAFM/CFM mounted on a toploading insert of a Leiden Cryogenics closed-cycle dilution refrigerator. The sample temperature was 60 mK during an AFM scan with a speed of 400nm/s. The images nicely demonstrates that the delicate microscope works very well even under these extreme conditions.

This measurement was realized with the attoAFM/CFM, and the attoAFM/CFM in Dry Dilution Refrigerator.


Atomically Flat Terraces atomic force microscope attoAFM

Atomically Flat Terraces

Image of atomically flat terraces on a 0.1° canted SrTiO3 surface using a standard attoAFM I made for cryogenic application. The height difference for each terrace is about 0.39 nm which demostrates the height resolution that is possible with the attoAFM I used with an attoLIQUID. Acquisition time for this 150 x 150 pixel image of size 2 x 2 µm2 (13 nm pixel size) was about 15 min.

(attocube application labs, 2007)

This measurement was realized with the attoAFM I.


KPFM of Au on Pt Pattern attoAFM for KPFM

KPFM of Au-on-Pt Pattern

The kelvin probe force microscopy (KPFM) measurements shown here were performed on a test sample consisting of a Au layer on a Pt substrate in dual pass mode at cryogenic temperatures of 4K. The KPFM image was recorded during the second line with a lift height of about 50 nm. The color scale spans approximately 130 mV, and the image size is 11.9 µm x 11.9 µm.We found a KPFM contrast of approx. 35 mV, and a KPFM resolution (noise level) of approx. 2.6 mV.

(attocube application labs 2014)

This measurement was realized with the attoAFM I.


Scanning Gate Microscopy at 300 mK

In this measurement, an attoAFM III was operated inside an attoLIQUID3000 cryostat at 300 mK in scanning gate microscopy mode (SGM) - investigating the trajectory and interaction of edge channels of a split-gate quantum point contact (QPC) device in the Quantum Hall (QH) regime. By scanning the SGM tip over the surface of the QPC at constant height and by simultaneously measuring and plotting the source-drain current, conductance maps were obtained. The image to the left is an example of such a conductance map depicting the characteristic branched-flow of electrons at zero magnetic field, which in turn shows electron interference fringes and the actual electron path (T = 400 mK, 2DEG density n2D = 3.37 x 1011 cm-2).

(Data and images were generously provided by S. Heun et al., NEST, CNR-INFM and Scuola Normale Superiore, Pisa, Italy.)

This measurement was realized with the attoLIQUID3000, and the attoAFM III in Dry Dilution Refrigerator.

Scanning Gate Microscopy at 300 mK attoLIQUID3000  attoAFM III

attoAFM III Mounted on Mixing Chamber attoAFM III  mK application

attoAFM III Mounted on Mixing Chamber

This AFM-topography test-measurement of an 20 nm high calibration grating was performed in a pulse-tube based dilution fridge from Leiden Cryogenics. Even though the sample was scanned with 3 µm/s, the temperature did not rise above 80 mK, while the base temperature of the (here not optimized) braid cooled sample was at around 62 mK. Geophone measurements verified the low vibrations of the platform and showed that it is a suitable approach for high resolution, ultra-low temperature AFM-type experiments.

(attocube applications in collaboration with Leiden Cryogenics, 2011)

This measurement was realized with the attoAFM III, and the attoAFM III in Dry Dilution Refrigerator.


Vortex Imaging via Scanning Hall Probe Microscopy SHPM

Vortex Imaging via Scanning Hall Probe Microscopy

SHPM measurements on a degraded Bi2Sr2CaCu2O8+x substrate have been performed demonstrating strong surface pinning effects at 4.2 K and 2.5 Gauss external magnetic field. The figure shows the vortex distribution measured in constant height of approx. 100 nm above the surface.

(attocube applications labs, 2011; sample courtesy of A. Erb, TU Munich, Germany)

This measurement was realized with the attoSHPM.


Domain Imaging in BaFeO SHPM

Domain Imaging in BaFeO

The 15 µm x 15 µm sized image shows a sample of BaFeO recorded with an attoSHPM, recorded at 4.2 K. The SHPM sensor was kept in a constant height of about 200 nm. The color scale spans 106 mT (dark to bright), while the S/N ratio of this measurement yields an exceptional 50 000:1. Note that SHPM records absolute field strength as opposed to MFM techniques, that record only field gradients.

(attocube application labs, 2011; sample courtesy of R. Kramer, Institut Néel, CNRS, Grenoble)

This measurement was realized with the attoSHPM.


MFM on Superconducting Vortices in BSCCO attoAFM for MFM

MFM on Superconducting Vortices in BSCCO

This measurement shows a dominantly hexagonally ordered Abrikosov votex lattice, at a magnetic field of -40 Oe (the sample was field-cooled) and liquid helium temperatures. The orientation of the vortices with respect to the moment of the tip is indicated by the color of the vortices: Bright colors indicate repulsive forces. The tip was scanned in a constant height of about 30 nm above the surface of a freshly cleaved piece of BSCCO-2212. Note that the applied field is much lower than the coercitivity of the hardmagnetic tip (≈400 Oe), hence the orientation of the tip moment is unchanged. Scan size is 10 x 10 µm2, color span is 2 Hz.

(attocube applications labs, 2013; sample courtesy of A. Erb, TU Munich, Germany)

This measurement was realized with the attoAFM I.


Helimagnetic Phase of FeCo0.5Si0.5 attoAFM for MFM

Helimagnetic Phase of FeCo0.5Si0.5

Real space imaging of exotic magnetic phases provides a level of understanding that cannot be achieved with indirect techniques. The figure on the left shows one of the first observations of a helimagnetic phase using the attoMFM I. The periodicity of the stripes is around 100 nm. This phase is of particular interest because of its proximity to a skyrmion phase. Skyrmions are exotic magnetic excitations, studied extensively because of their potential use in spintronic applications. The measurement was performed on a FeCo0.5Si0.5 sample at cryogenic temperature (4K) using an attoMFM I inside a liquid helium cryostat (attoLIQUID).

(attocube application labs, 2013; sample courtesy of A. Bauer and C. Pfleiderer, Technical University of Munich, Garching, Germany)

This measurement was realized with the attoAFM I.


High Resolution MFM on Bit Patterned Media Co Pd at 10K attoAFM for MFM

High Resolution MFM on Bit Patterned Media Co-Pd at 10K

MFM measurement on Co-Pd dots with 50 nm diameter at 10 K using the attoMFM I. The image demonstrates the high magnetic resolution achievable with the attoMFM at cryogenics. Variations in magnetic field perpendicular to the surface allows switching domains from one magnetic state to the other (here recorded at 6250 Oe). For this measurement, the attoMFM was operated at constant height with the frequency shift measured using a phase-locked loop.

(attocube application labs, 2010; sample courtesy of Hitachi Global Storage Solutions, San Jose, USA)

This measurement was realized with the attoAFM I.


Conductive Tip AFM Measurements on Ruthenium ct   atomic force microscope attoAFM

Conductive-Tip AFM Measurements on Ruthenium

In this application, atomic steps on Ruthenium were investigated using conductive-tip AFM. Atomic steps as well as spiral dislocations can be identified on the molecular beam epitaxy-grown sample. The contrast in this measurement is highly enhanced due to a difference in conductance between edges and flat plateaus. Such high contrast was not observed in the accompanying topographic image. A voltage of +10 mV was applied to the standard Pt-coated AFM tip, while the sample was grounded via a current amplifier with gain 106 V/A. The measurement was performed at room temperature in a 20 mbar He atmosphere.

(Sample and measurement courtesy of V. Da Costa, J.-F. Dayen, B. Doudin, IPCMS-DMONS,CNRS/University of Strasbourg, France)

This measurement was realized with the attoAFM I.


Link between bulk electric and microscopic magnetic properties of LaPryCaMnO made with the low temperature atomic force microscope

Link between bulk electric and microscopic magnetic properties of LaPryCaMnO

A research team around Prof. Jian Shen from the low-dimensional material physics group at Fudan University (China) has studied extensively thin films of manganites (LaPrCaMnO on SrTiO). This family of materials has very unique electronic and magnetic properties, which can be tailored for all sorts of spintronic and electronic applications.
Their findings have been published in a series of 5 papers, in which they have been using an attoAFM/MFM Ixs in an attoDRY1000 & PPMS to characterize the microscopic origins of a magnetic and electronic phase separation at low temperatures and in high magnetic fields controlled by nanopatterning as well as shedding light on the connection between bulk electric and microscopic magnetic properties of such films.

This measurement was realized with the attoAFM I.


attoAFM III in Toploading Insert attoAFM III  mK application

attoAFM III in Toploading Insert

The depicted data was taken with a tuning fork attoAFM III specifically designed for mK operation. The extremely sensitive microscope was mounted on a toploading insert (see images and project description on the left page), which ensures a much higher usability in terms of turnaround times upon tip and sample exchange than if it were mounted directly on the mixing chamber. The sample temperature in the toploading DR was 55 mK during the scan at 100 nm/s. The images nicely demonstrates that the delicate microscope works reasonably well even under these extreme conditions.

This measurement was realized with the attoAFM III, and the attoAFM III in Dry Dilution Refrigerator.


In situ AFM measurements of SrTiO3 and Co particles inside an electron microscope made with attoAFM III

In-situ AFM measurements of SrTiO3 and Co particles inside an electron microscope

attocube systems offers a comprehensive line of products which are compatible with ultra high vacuum and cryogenic conditions. In this context, we have extended our product family by developing an Atomic Force Microscope (AFM) series designed for in-situ use in­side Scanning Electron Microscopes (SEM) or environmental SEM. This series of ultra-compact AFMs allows scientists to perform high-resolution topographic, magnetic, or tensile strength measurements in material science, structural biology, solid state physics, and other fields of nanotechnology. Depending on the specific application, two different AFM versions are available: a cantilever based AFM with interferometric deflection detection and a tuning fork AFM.

This measurement was realized with the attoAFM III.


attoAFM I Mounted on Mixing Chamber attoAFM  mK application

attoAFM I Mounted on Mixing Chamber

This scan above nicely demonstrates the stability of a complete system, an attoAFM I together with a LD400 cryo-cooler from BluFors Cryogenics. For this 25 x 25 µm2 (800 x 800 pixel) scan, the pulse-tube cooler was enabled the whole time. The temperature was stable at ≈40 mK measured at the mixing chamber - it was slightly higher due to the higher scan speed of close to 1 µm/s.

(attocube applications in collaboration with BluFors Cryogenics, 2014)

This measurement was realized with the attoAFM I.


Magnetic Force Microscopy Specifications in attoDRY1100 on par with Liquid Cryostats made with attoDRY1000 and attoAFM

Magnetic Force Microscopy Specifications in attoDRY1100 on par with Liquid Cryostats

In this application note, we show examples of magnetic force microscopy measurements performed in the pulse-tube based, fully automated attoDRY1100 cooling system. The attoDRY1100 cryogenfree magnet system redefines the state of the art of MFM, with specifications close to those reached in a regular liquid bath cryostat.

This measurement was realized with the attoDRY1100, and the attoAFM I.


HF SPM using attocube nano positioners in magnetic fields above 30 T cryogenic positioner  ANPz30

HF-SPM using attocube nano-positioners in magnetic fields above 30 T

In an outstanding setup, Benjamin Bryant and Lisa Rossi (High Field Magnet Laboratory, Radboud University, Nijmegen, NL), together with the SPM group of Alex Khajetoorians (Radboud University), designed a high field scanning probe microscope (HF-SPM) for operation at cryogenic temperatures and in extreme magnetic fields up to 38 T. The high magnetic field is provided using a water-cooled Bitter magnet: noise from the cooling water creates a highly challenging vibration environment for SPM. An ANPz30 nanopositioner controls the coarse approach of an atomic force microscope cantilever to a scanned sample. The attocube positioner provides for a modular design that makes it easy not only to change the components if needed but also allows the flexibility to employ different cantilever or sample holders. Due to the compactness and rigid design of the positioner the sensitivity to vibrational noise is reduced, which is critical for SPM in the extreme environment of the Bitter magnet.

This measurement was realized with the ANPz30/LT - linear z-nanopositioner.


Piezo-Controlled Exfoliation of Graphene

In the group of Prof. Gosh at the IIS in Bangalore, researcher Kinikar and his coworkers managed to measure the conductance of narrow stripes of graphene during their exfoliation. A metal tip is crashed into a graphite HOPG crystal using an attocube positioner for vacuum application, namely the ANPz101, and slowly retracted via a piezo tube. Conductance is measured from the tip through the HOPG crystal. The setup situated inside a SEM is shown in picture 1. The graphite piece sticking on the tip will thereby be torn to a single layer of graphene. Mechanically torn graphene has highly crystalline edges, leading to quantized conductance. This is due to one-dimensional channels forming at the edges each with a conductance of 2e2/h (graph 2). A similar setup was used in a cryostat for high magnetic field measurements.
Kinikar: “The attocubes have been with us for over a decade, and they still work perfectly!”

This measurement was realized with the ANPz101/HV - linear z-nanopositioner.

Piezo Controlled Exfoliation of Graphene cryogenic nanopositioner ANPz101 HV
Piezo Controlled Exfoliation of Graphene cryogenic nanopositioner ANPz101 HV

mK STM Image with Atomic Resolution  cryogenic nanopositioner  ANPz51 LT

mK STM Image with Atomic Resolution

STM image of an aluminum (100) surface with atomic resolution. The image size is about 29 x 20 nm2. The corrugation is between 300 fm and 800 fm, depending on the direction of the line profile. Defects show up as ring-like structures with different radii depending of their depth. The image was measured in a homebuilt mK-STM at the Max-Planck Institute for Solid State Research in Stuttgart, which uses a cryogenic attocube ANPz51 positioner for coarse approach.

(Image courtesy of Department of K. Kern, Max-Planck Institute for Solid State Research, Stuttgart, Germany)

This measurement was realized with the ANPz51/LT - linear z-nanopositioner.


Scanning Hall Probe Microscopy at 300 mK with ANP positioners made with Low Temperature Nanopositioners

Scanning Hall Probe Microscopy at 300 mK with ANP positioners

The magnetic properties of superconducting and ferro­magnetic materials at ultra-low temperatures represent some of the most interesting contemporary problems in condensed matter physics. These properties are typically investiga­ted using a magnetic force microscope or a scanning Hall probe microscope (SHPM). In this note, we report on a self-built SHPM capable of working at temperatures as low as 300 mK and magnetic fields of up to 10 T, while still having sub-micron lateral spatial resolution.

This measurement was realized with the ANPx101/LT - linear x-nanopositioner, and the ANPz102/RES/LT - linear z-nanopositioner.


Photoluminescence measurements in fields up to 28 T made with cryogenic nanopositioners

Photoluminescence measurements in fields up to 28 T

The attocube systems positioners ANPxyz100/LT have been used in a setup for optical measurements in liquid 4He temperature and ma­gnetic fields up to 28 T at the Grenoble High Magnetic Field Labo­ratory. In the setup laser excitation is delivered using a single-mode fiber and is focused onto the sample with two microlenses. A multimode fiber is used for photoluminescence (PL) collection.

This measurement was realized with the ANPx101/LT - linear x-nanopositioner, and the ANPz102/RES/LT - linear z-nanopositioner.


Imaging fractional incompressible stripes in integer quantum Hall systems using the attoAFM III made with attoAFM III in attoLIQUID300 for mK application

Imaging fractional incompressible stripes in integer quantum Hall systems using the attoAFM III

Nicola Paradiso, Stefan Heun, and co-workers measured the fractional quantum Hall effect in quantum point contacts using an attoAFM III in an attoLIQUID3000 at very low temperature (300 mK) and high magnetic field (≈8 T). They demonstrated that fractional features were unambiguously observed in every integer quantum Hall constriction. These ground-breaking Scanning Gate Microscopy experiments pave the way to a better understanding of the role of fractional phases in the field of coherent quantum transport!

This measurement was realized with the attoAFM III, and the attoLIQUID3000.


Low Temperature Surface Piezoelectricity in SrTiO3 using an attoAFM I for Piezo Response Force Microscopy made with the low temperature atomic force microscope

Low Temperature Surface Piezoelectricity in SrTiO3 using an attoAFM I for Piezo-Response Force Microscopy

SrTiO3 is one of the most investigated materials from the ferroelectric perovskite titanates family due to the variety of physical phenomena ranging from incipient ferroelectricity to superconductivity. Nowa­days, considerable interest to SrTiO3 is conditioned by the observations of additional anomalies in the quantum paraelectric regime of SrTiO3, which could be described in terms of a coherent quantum state occurring below T≈37 K. It is supposed that these anomalies are rela­ted to the existence of large polarization clusters. Visu­alizing the dynamic of ferroelectric nanoscale structure at low temperatures may shed light on the mechanisms of the T≈37 K anomaly.

This measurement was realized with the attoAFM I.


Dynamic Visualization of Nanoscale Vortex Motion using attoSTM in an attoLiquid3000 made with AFM STM for mK application

Dynamic Visualization of Nanoscale Vortex Motion using attoSTM in an attoLiquid3000

Matias Timmermans and co-workers invented an innovative technique removing the lack of temporal resolution in STM imaging. They used an attoSTM in an attoLIQUID3000 3He cryostat to measure and study vortex motion in 2H-NbSe2 on a much shorter time scale. By applying a small AC magnetic field they induced a periodic movement of the vortices. The external perturbation results in a distinct smearing of the vortex in the images. Instead of collecting several consecutive images, the tunnelling current is recorded at each point over three cycles of the excitation. The exceptional thermal and spatial stability of the attoSTM in the attoLiquid3000 allows further analysis of the time dependence of this signal at each point. Using an additional lock-in technique more details and understanding of the vortex motion is revealed. By mapping the first and a second harmonic of the tunnelling signal (see upper figures), they were able to visualize changes of the vortex lattice when the vortex density is increased by increasing the DC magnetic field.
In a next step, they used the AC excitation as a time reference to track the motion of individual vortices in time. This results in time resolved snapshots of the vortex motion, which allows them to construct a movie frame by frame. This visualization procedure is unprecedented and promises a much better understanding of the dynamical behaviour of the superconducting condensate (see lower figures). Contrary to the expectation the vortex does not move in a line but follows a circular motion, due to a potential created by atoms and/or vortices.

This measurement was realized with the attoAFM III, and the attoLIQUID3000.


Piezo Response Force Measurements on Ferroic Oxide Films using the attoAFM I made with the cryogenic atomic force microscope

Piezo-Response Force Measurements on Ferroic Oxide Films using the attoAFM I

The renaissance of multiferroics in which at least two ferro­ic or antiferroic orders coexist, is motivated by fundamental aspects as well as by their possible applications in the field of spintronics. Magnetoelectric coupling allows for instance the reversal of the ferroelectric polarization by a magnetic field or the control of the magnetic order by an electric field. Most of the ferromagnetic-ferroelectric compounds exhibit both orders at low temperature.

This measurement was realized with the attoAFM I.


Vortex Barriers in Iron Pnictides  attoLIQUID  attoAFM

Vortex Barriers in Iron Pnictides 

Iron-pnictide high-temperature superconductors are widely studied, but many open questions still remain. Using an attoAFM I for magnetic force microscopy, the group of O. Auslaender has studied twin boundaries and their interaction with vortices over a range of magnetic fields and temperatures. They find that stripes parallel to the twin boundaries repel vortices, effectively hindering vortex motion, and hence potentially affecting the critical current in such materials.

(Data courtesy of O. Auslaender, Technion, Israel)

This measurement was realized with the attoLIQUID1000, and the attoAFM I.


Internal magnetic fields in natural sands

In this application, samples of natural sand were investigated with a cryogenic sSQUID as described above. The measurements indicate large internal magnetic field variations over tens of microns with up to 2 mT, as well as variations in excess of 50 µT over smaller ranges. These findings clearly show that unaccounted internal fields can significantly alter NMR data in unknown samples.

This measurement was realized with the Scanning SQUID Platform.

Internal magnetic fields in natural sands SQUID platform
Internal magnetic fields in natural sands SQUID platform

MFM for Optimization of Sintered Magnets attoAFM for MFM

MFM for Optimization of Sintered Magnets

MFM image of a NdFeB sintered magnet with the nominal c-axis orientation perpendicular to the surface. The sample is in the remanent state but some surface grains show already magnetization reversal. High resolution imaging allows deeper insights into the magnetic reversal mechanism and the optimization of magnetic properties. Image size is 30x30µm2.

(Image courtesy of T. Helbig and O. Gutfleisch, Functional Materials Group, TU Darmstadt, Germany and Fraunhofer IWKS Hanau, Germany.)

This measurement was realized with the attoAFM I.


Angle-dependent characterizations of materials

Attocube's rotators offer a way to use the full magnetic field of a 1D magnet for field-angle dependent transport measurements at the sample. This benefit is used by the group of Anne de Visser at the Van der Waals - Zeeman Institute (University of Amsterdam, NL) in two setups with an ANR51 and an ANRv220 both in a closed loop configuration.
Magnetotransport measurements as a function of the angle θ in the trigonal basal plane of the topological superconductor SrxBi2Se3 revealed a large two-fold anisotropy of the upper critical field Bc2. Such a rotational symmetry breaking of Bc2(θ) cannot be explained with standard models, and indicates unconventional superconductivity with an exotic order parameter. More about this work can be found at [1].
In the second setup a home-built compact dilatometer was mounted on the ANRv220 in a dilution refrigerator. This was used to measure the anisotropy in the ferromagnetic and superconducting phase diagram of a single crystal of UCoGe by applying magnetic fields up to 14 T along the different crystallographic axes [2].

This measurement was realized with the ANR51/RES/LT - rotator (360° endless), and the ANRv220/RES/LT - rotator (360° endless).

Angle dependent characterizations of materials cryogenic nanopositioner  ANR51 RES LT  ANRv220 RES LT
Angle dependent characterizations of materials cryogenic nanopositioner  ANR51 RES LT  ANRv220 RES LT

Low Temperature Piezoresponse Force Microscopy on BiFeO attoAFM for PFM

Low Temperature Piezoresponse Force Microscopy on BiFeO

Piezoresponse Force Microscopy (PFM) is a standard tool at room temperature to investigate new materials, especially multiferroics. However, in many cases the scientifically interesting phases only exist at low temperatures or high magnetic fields, what demands the extension of this technique to extreme conditions. In collaboration with our customers, we adapted our attoAFM based on the general purpose ASC500 for PFM measurements. In the measurements shown on the left, we investigated BiFeO3 a well know room temperature multiferroic. The figure shows piezoresponse amplitude after a box in the box writing at 160 K on the sample.

(attocube application labs, 2013; Sample courtesy of Neus Domingo & Gustau Catalan, CIN2 Barcelona, Centre d’Investigació en Nanociència i Nanotecnologia, Bellaterra, Spain)

This measurement was realized with the attoAFM I.


Local Conductivity Mapping and PFM on BFO Thin Film

In this application, the versatility of the cryogenic attoAFM I was demonstrated on an ultra-thin film of BFO. A simple box writing and reading measurements was performed. During the writing phase, a DC voltage of -10 V was applied to write a box. For the reading, a 5 Vpp AC excitation at ≈42 kHz on top of a -2 V DC voltage was used. Combining both AC and DC voltage at the same time allows for a simultaneous measurement of PFM (right image) and local conductivity (left image).

(attocube application labs, 2014; sample courtesy of N. Domingo, ICN Barcelona, Spain)

This measurement was realized with the attoAFM I.

Local Conductivity Mapping and PFM on BFO Thin Film attoAFM for ct AFM
Local Conductivity Mapping and PFM on BFO Thin Film attoAFM for ct AFM

Quantized Conduction on Domain Walls of a Magnetic Topological Insulator attoLIQUID3000  attoAFM

Quantized Conduction on Domain Walls of a Magnetic Topological Insulator

In a paper published in Science, researchers from the University of Tokyo and RIKEN (Japan) have studied “Quantized conduction on domain walls of a magnetic topological insulator” using an attoAFM/MFM in a 3He-cryostat down to 500 mK. In their paper, Yasuda et al. designed and fabricated magnetic domains in the quantum anomalous Hall state, and proved the existence of the chiral one-dimensional edge conduction along the domain walls through transport measurements.
This discovery would permit fully electrical control of the mobile domain walls and chiral edge states, which may lead to the realization of low-power-consumption spintronic, memory and quantum information processing devices in the future.

This measurement was realized with the attoLIQUID3000, and the attoAFM I.


Piezoresponse Force Image on BFO attoAFM for PFM

Piezoresponse Force Image on BFO

This image shows the attocube logo electrically written into a BaFeO3 substrate next to natural domains of the sample. The data were taken at cryogenic temperature of 4 K in piezoresponse force mode using an attoAFM I inside a liquid helium cryostat. Image size is 5 x 5 µm2.

This measurement was realized with the attoAFM I.


Measurements of field-driven transformation of a domain pattern

The group of Erik Folven at the Norwegian University of Science and Technology (Trondheim, Norway) used an attoAFM I for MFM measurements with a closed cycle attoDRY1000 to demonstrate how topological defects may be invoked to understand magnetic domain state transitions. The atomically sharp and magnetized tip of the microscope is scanned across the thin film surface to pick up the out-of plane stray fields from the sample and thus is sensitive primarily to spin textures such as domain walls and defects. The MFM measurements taken at 5K help to understand and describe micromagnetic domain state transitions and to assess their stability in remanence. This insight may open for new approaches to control the switching properties of micro- and nanomagnets.

This measurement was realized with the attoDRY1000, and the attoAFM I.

Measurements of field driven transformation of a domain pattern closed cycle cryostat attoDRY1000  attoAFM  atto3DR oder attoTMS

A new way to modulate exciton-complex emissions of TMDs

A new type of atomically layered transition-metal dichalcogenides (TMD) was developed by Mr. Taishen Li and co-workers from the University of Science and Technology of China (Hefei, China): a triangular inkslab-like WSe2 homojunction with a monolayer in the inner surrounded by a multilayer frame.Optical and scanning photocurrent microscopy (SPCM) measurements performed with the attoCFM I, cooled by a closed cycle attoDRY1000 to cryogenic temperatures, shows a clear redshift of the photoluminescence peaks from the center to the edge region of the inner monolayer, reflecting a high charge density gradient. In addition, a significant rectifying behavior and photovoltaic response across the homojunction is observed. All in all, the results lead to efficient modulation of the exciton-complex emissions of TMDs.

This measurement was realized with the attoDRY1000, and the attoCFM I.

A new way to modulate exciton complex emissions of TMDs closed cycle cryostat attoDRY1000  attoCFM  atto3DR oder attoTMS
A new way to modulate exciton complex emissions of TMDs closed cycle cryostat attoDRY1000  attoCFM  atto3DR oder attoTMS

Ultimate Thermal Stability and Ultra-Low Drift

In order to characterize both the low-frequency drift of the atomic force miroscope unit of the attoCSFM with respect to the sample, a carbon nanotube (CNT) was imaged (a). By scanning the same line across the CNT (green line in overview image) 500 subsequent times within 42 minutes (b), a line-to-line position jitter below 1 nm and a long-term drift of less than 3 nm were observed (c), demonstrating the outstanding thermal and mechanical stability of the attoCSFM. After several hours of thermalization, drifts below 1 nm/h can be achieved (d). The part of drift due to scanner creep is constantly monitored interferometrically and can therefore be corrected.

(attocube application labs, 2012; sample courtesy of A. Hartschuh, LMU Munich, Germany)

This measurement was realized with the Combined Atomic Force & Confocal Microscope.

Ultimate Thermal Stability and Ultra Low Drift CSFM
Ultimate Thermal Stability and Ultra Low Drift CSFM