German nanotechnology specialist attocube offers scanning probe microscopes to study the behaviour of complex magnetic nanostructures at ultralow temperatures
"Cool technologies, cold science: attocubeu2019s close connections with leading research scientists facilitate the development of its broad portfolio of nanopositioners, cryostats, scanning probe and confocal microscopes, and other low-temperature measurement tools. (Courtesy: attocube)" Cool technologies, cold science: attocube’s close connections with leading research scientists facilitate the development of its broad portfolio of nanopositioners, cryostats, scanning probe and confocal microscopes, and other low-temperature measurement tools. (Courtesy: attocube)Pushing the boundaries of nanoscale imaging while embracing the extremes of ultralow operating temperatures. That’s the core value proposition offered by attocube, a German manufacturer of specialist nanotechnology solutions for research and industry, when it comes to the design, development and optimization of its portfolio of scanning probe microscopes (SPMs) and related accessories.
Despite the complexities associated with cryogenic operation, the attocube product design team is intent on bridging the gap between room-temperature SPM and ultralow-temperature applications. In short: the realization of versatile and easy-to-use SPM instrument platforms spanning a range of modalities, including (but not limited to) atomic force microscopy (AFM), conductive-tip AFM, magnetic force microscopy (MFM), piezo-response force microscopy and Kelvin probe force microscopy.
A “lighthouse customer” in this regard is Stuart Parkin, whose team at the Max Planck Institute for Microstructure Physics in Halle, Germany, is using the attocube MFM (an attoAFM I microscope with an attoMFM upgrade in an attoLIQUID2000 cryostat) to study the physical properties of materials systems with possible applications in so-called “racetrack memories”. This early-stage technology, the basic principles of which were originally elaborated by Parkin in 2002, represents a promising candidate for next-generation solid-state, non-volatile memory devices that exploit the current-controlled motion of magnetic domain walls in magnetic nanowires.
Magnetism deconstructed
The broader commercial drivers here – ultrahigh-density storage capacity and significantly enhanced energy efficiency – are rooted in fundamental materials physics. Not least the fact that racetrack memories are innately three-dimensional – in contrast to the inherent 2D structure of both magnetic disk drives (with data stored in a single 2D sheet of magnetic material) and silicon-based microelectronics (in which logic is carried out using a single sheet of transistors fabricated in the surface of single-crystal silicon).
"Stuart Parkin: u201cItu2019s clear that attocube builds products with a lot of forethought and consideration to take advantage of emerging research opportunities.u201d (Courtesy: Max Planck Institute for Microstructure Physics)"Stuart Parkin: “It’s clear that attocube builds products with a lot of forethought and consideration to take advantage of emerging research opportunities.” (Courtesy: Max Planck Institute for Microstructure Physics)Right now, Parkin and his team are focused on understanding the underlying physical properties of a specific class of magnetic nanostructure – known as topologically protected, non-collinear magnetic domain walls – while evaluating their potential utility as a vehicle for fast and energy-efficient data transfer in future racetrack-memory devices. “What we want to do is image these magnetic textures down to the nanoscale,” explains Parkin. “It’s not so easy, though – there aren’t many ways to do this effectively.”
One approach that’s being pursued in Parkin’s laboratory is Lorentz transmission electron microscopy – a powerful tool to study crystal and magnetic domain structures in correlation with novel physical behaviours. The downside, however, is that this imaging modality requires the scientist to make very thin, electron-transparent laminar membranes of the sample so that the electron beam can pass through – a significant overhead in terms of research productivity and output. “Sample preparation is tricky, time-consuming and can also damage the material under study,” notes Parkin.
Positioning for success
Conversely, sample preparation is a lot simpler for cryo MFM imaging (as the grown sample just has to be glued to the sample holder and contacted electrically prior to cool-down and measurement). In terms of specifics, the attoAFM I works by scanning the sample below a fixed cantilever and measuring deflection of the latter with a fibre-based optical interferometer to reconstruct the magnetic texture of the sample surface (with a lateral resolution of
