Magnetic racetrack memories

It’s sobering to think that the hard disk drive is now 50 years old, and yet as a data storage technology it is still about 100 times more cost effective than its competitors. Yet its drawbacks are pretty apparent – hard drives are inherently slow and unreliable, and because of the mechanical nature of the device this is not likely to change fundamentally. Meanwhile various solid state memories, like SRAM, DRAM and flash memory, are very fast-growing market segments. Yet even with the continual shrinking of circuit dimensions, these technologies will not be able to match the raw storage capacity of hard drives. The search is on, then, for memory devices that have the capacity of hard drives but the robustness and speed of access of solid state devices. One candidate for such a device is the magnetic racetrack, invented by IBM’s Stuart Parkin. One needs to take Parkin’s views on magnetic data storage devices very seriously; as the inventor of the giant magnetoresistance based read head, it’s his work that has permitted the miniaturisation of hard disks that we see today and which makes possible devices like the video iPod.

I heard Parkin speak about his invention at last week’s Condensed Matter and Materials Physics meeting of the Institute of Physics, where he was one of the plenary lecturers. A version of this lecture, which Parkin recently gave at UCSB, can be downloaded from here – this includes some very helpful videos. Parkin’s invention is disclosed in this US patent; the basic idea is that data is stored in a pattern of magnetic domain walls in a nanowire of a magnetic material, which needs to be about 10 microns long and less than 100 nanometers wide. Rather than reading the pattern of magnetic domains by moving a read-head along the wire, in the magnetic racetrack the wire is held stationary and the magnetic domains are swept past a stationary read-head by applying a current. There’s a lot of fascinating physics in the way a current can move the domain walls, but the attraction of this arrangement from a practical point of view is that there are no moving parts, and the data density can be very high. Parkin envisages an array of these nanowires, each bent in a U-shape, with the bottom of the U held against a read head and a write head which are laid down by conventional planar silicon technology. It’s this compatibility with existing manufacturing technology that Parkin sees as a compelling advantage of his idea, as compared with other proposals for high density data storage devices depending on more exotic schemes using, for example, carbon nanotubes.

Hollow centre: Nanotechnology is a discipline in the throes of an existential crisis

This review of “The Dance of Molecules : How Nanotechnology is Changing Our Lives”, by Ted Sargent, is published in today’s edition of Nature. The published version differs slightly from this unedited text, which is reproduced here by permission of Nature, and should not be further reproduced.

Every field needs its founding genius; the appropriately mythic figure for many in nanotechnology is Richard Feynman, on the strength of his 1960 lecture “There’s plenty of room at the bottom”. Yet this particular canonization is entirely retrospective; there’s little evidence that this lecture made much impact at the time, and Feynman rarely returned to the topic to develop his thoughts further. Perhaps a better candidate to be considered nanotechnology’s father figure is President Clinton, whose support of the USA’s National Nanotechnology Initiative converted overnight many industrious physicists, chemists and materials scientists into nanotechnologists. In this cynical (though popular) view, the idea of nanotechnology did not emerge naturally from its parent disciplines, but was imposed on the scientific community from outside. As a consequence, nanotechnology is a subject with an existential crisis – is there actually any firm core to this subject at all, any consensus as to what, at heart, defines nanotechnology?

This is the problematic territory that Sargent has tried to map out for the popular reader in “The Dance of Molecules”. How then, does Sargent deal with this tricky question of definition? “Nanotechnologists”, he says, “have as their goal to design and build matter to order, specified by a functional requirement”. This is fine, but it may leave followers of an earlier new discipline – Materials Science – puzzled, as this was their slogan too. He begins by maintaining the centrality of quantum mechanics, but really this is just an assertion of the centrality of chemistry. The title “The Dance of Molecules” might suggest the idea of Brownian motion, but this idea isn’t pursued. In the end he is forced to conclude that nanotechnology’s central theme isn’t scientific, but sociological – a new culture of interdisciplinarity that searches for convergence between increasingly atomized scientific fields.

There is one version of nanotechnology that does have clarity – K. Eric Drexler’s vision of scaled-down mechanical engineering. It is this revolutionary vision that underlies much of the popular image of nanotechnology, promoted through science fiction, films and computer games. Yet very few scientists take this version of nanotechnology seriously. This leaves a problem for popularizers who wish to reflect the scientific consensus. One can rebut these claims in detail, or one can simply dismiss them with appeals to the authority of distinguished scientists like the late Richard Smalley. Sargent takes a third course; he simply does not mention them. This seems to me to be the most unsatisfactory approach of all; if one thinks the Drexler vision is wrong, one should say so, otherwise the reading public, who are extensively exposed to these ideas, will be left very confused.

Lacking a strong science core, the book is written thematically, as a tour of application areas in health, environment and information. Quantum dots make frequent appearances, there’s quite a good description of molecular electronics, which is duly circumspect about the balance of potential and practical difficulty. The descriptions of bionanotechnology carry less conviction – the description of molecular motors seems particularly misleading. Many people will find the rather overwrought style irritating – perhaps the oddest of the many strange and strained metaphors and similes is his description of photolithography as being “like crop circles formed when the sun blazes through round partings in the English permacloud”.

Nanotechnology, above all an applied science, has been the subject of a possibly unprecedented push for early consideration of social, environmental and ethical impacts. Here the rhetoric is overwhelmingly positive, and the need for public engagement seen solely in terms of defusing possible opposition. We’re promised an end to cancer, the restoration of sight to the blind, and, via unconventional solar cells and the hydrogen economy, an end to our dependence on fossil fuels for energy. The possible downsides are largely limited to the potential toxicity of some nanoparticles. Even in military applications, the emphasis is on defensive applications and on the possibility that nanotechnology will make it much easier for the west to wage a “clean war”, in which combatants are easily distinguished from non-combatants. I don’t think you need to be a radical anti-technology activist to greet this claim with some scepticism.

The current difficulties of nanotechnology include its incompletely formed disciplinary identity and lack of clear definition, the overselling of its immediate potential economic and societal impacts, and its association with extreme utopian and dystopian futuristic visions. A good popular book could contribute to overcoming these difficulties by setting out a clear set of core scientific principles that underpin nanotechnology, making realistic claims for what applications and impacts will be possible on what timescale, and presenting a more sophisticated understanding of the relationships between science, the economy and society. This book does not fulfill this need.

A quiet policy shift for UK nanotechnology

The centrepiece of the UK’s publically funded nanotechnology effort has been the Department of Trade and Industry’s Micro and Nanotechnology manufacturing initiative (MNT). This had a high profile launch in July 2003 in a speech by the science minister, Lord Sainsbury, with an initial commitment of £90 million. When, last year, the Secretary of State for Trade and Industry announced an increase of DTI nanotechnology funding to £200 million, the future of the MNT program seemed assured. But a close reading of recent announcements from the DTI make it clear that whatever extra funding they may be putting into nanotechnology, it’s not going into the MNT program.

Technology and innovation policy at the DTI is now informed by a Technology Strategy Board, made up largely from figures from industry and venture capital. This board’s first annual report (PDF) was published in November 2005, and contained this recommendation:
“We also recommend incorporating nanotechnology in the competitions for underpinning technologies, such as advanced materials, to avoid confusion. It is important, however, that the DTI keeps track of expenditure on nano-projects to be able to honour its commitments to Parliament in this area.”

It’s now clear that this recommendation has been followed. The spring competition for collaborative R&D, announced here, and to be formally launched on April 26th, does not include a separate micro- and nano- theme. Instead, the call is based around what the DTI calls innovation platforms – societal challenges which many technologies can be combined to address. Undoubtedly, some of these areas will call for nano- enabled solutions. Novel Technologies For Low-Cost, High Efficiency Electronics And Lighting Systems mentions plastic electronics and light emitting diodes as potential technologies of interest, while Low Carbon Energy Technologies talks about the need for novel solar cells.

This is an interesting shift of emphasis. The MNT program had few friends in the world of academic nanoscience and technology; it always seemed happier with the micro- than the nano- , and the insistence that programs be business-oriented seemed on occasion to shade into a positive antipathy to academic nanoscience and led to the perception that the program was considerably friendlier to consultants than either technologists or scientists. On the other hand, the idea of building an applied research program around problems to be solved, rather than technological solutions looking for problems, seems one that is well worth trying.

What needs to happen for this to work? Firstly, the ongoing MNT program needs to become much more effective at connecting the best parts of the UK nanoscience base to potential users of the new technologies, and it needs to give more impression of being a little more forward looking in the technologies it’s sponsoring. Then the Technology Program is going to have to work hard to make sure that the right scientists are engaged and nanotechnology gets an appropriate share of the resources, meeting the very specific commitment to a certain level of spending on nanotechnology made by the Minister.

It’s going to be important to get this right. As I discussed a couple of weeks ago, there’s growing evidence of an external perception of the UK nanotechnology program as being diffuse, unfocused and ineffective. Given the general strength of the UK science base, the UK should be in a much better position; there’s a real danger that this could turn into a big missed opportunity.

Printing silicon

The main driving force for developing plastic electronics – the use of semiconducting polymers to make logic devices, light emitting diodes and displays, and solar cells – is the hope that these materials can be processed very cheaply. Because these materials are soluble, devices can be made by processes like ink-jet printing or screen printing. Compared to standard silicon-based electronics, the performance of these devices is often not very good, but the fact that you won’t need the massive capital expenditure of a conventional silicon fab tilts the economics towards the plastic materials, at least for applications where cost is more important than performance. But Nature this week reports an interesting twist – a group from the Seiko-Epson labs in Japan report a new way of printing silicon directly from solution (see also the Epson press release here).

The method is based on using polysilane as a precursor material. Polysilane is essentially the silicon based analogue of the well-known polymer polyethylene, consisting of a long chain of silicon atoms, each of which has two hydrogen atoms attached. But unlike polyethylene, polysilane is both unstable and very difficult to work with, being insoluble in most common solvents. The Japanese group got over this problem by starting with a five-membered ring version of the polysilane molecule – cyclo-pentasilane (this is the silicon analogue of cyclopentane). They found that polysilane was soluble in solutions of this precursor, and these solutions could be ink-jet printed and converted into pure silicon layers by a simple heating step.

The silicon layers formed this way are amorphous, not crystalline, and their electronic properties are not very good compared to silicon films prepared by more conventional routes (though they are better than most polymer semiconductors). Plastic electronics still has some advantages over this new process, which requires temperatures too high for the use of plastic substrates. The printing step is also complicated by the need to exclude water and oxygen. Nonetheless, it’s an important step forward towards the development of low-cost electronics for applications like large area displays and cheap solar cells.

Some reflections on UK nanotechnology policy

The think-tank Demos today released a report, Governing at the Nanoscale: People, policies and emerging technologies. I was one of the speakers at the launch event in London. This, more or less, is what I said.

It’s a pleasure to be asked to give my reactions to “Governing at the Nanoscale”, the latest of a very interesting set of pamphlets from Demos about the relationship between science and society. I’m responding as a scientist who participated in the public engagement aspects of the project, so I’d like to make some personal comments about the experience of public engagement from the scientist’s point of view. Then I’ll go on to make some more general comments about the way UK policy in this area has developed.

As you have seen from the film of the project, I had a lively time at the “Nanoscientists meet nanopublics” event held in the autumn. I’m struck by the editing of the film, which makes it clear that engaging with the public doesn’t necessarily mean agreeing with them! But scientists can derive a great deal from this sort of event, which prompt them to develop a richer picture of the relationships between the science they do themselves and the wider field that they work in with society and the economy.

For me, this event wasn’t an isolated one – it was one of some 21 public engagement events of one kind or another that I’ve taken part in in person over the last couple of years. I mention this not just to blow my own trumpet, but to emphasise the time taken up by a serious attempt to become involved in public engagement work. The rewards of this kind of effort are very great, but to be realistic one also needs to recognise the considerable disincentives that the way science is organised in the UK places in the way of this kind of activity.

Institutionally, public engagement brings no reward at all to the scientists who participate in it. University scientists working in physics, chemistry and materials science departments live and work in an atmosphere of insecurity – the financial pressures on these departments is very great and the threat to their future is very real, as we see in the recent machinations over the closure of Sussex’s chemistry department – the former home, of course, of Britain’s most famous Nanotechnology Nobel Laureate, Sir Harry Kroto. In this atmosphere, academic scientists need to focus on two things – directly raising contract and grant money to keep their departments afloat financially, and putting out high impact academic publications, to ensure a high grade in the Research Assessment Exercise, on which the very survival of departments depends. Public engagement is good for the discipline as a whole, but a Head of Department advising a young scientist is likely to urge him or her to concentrate on getting grants and writing papers for the RAE. Recent policy developments – the advent of full economic costing and the possibility of the RAE being replaced by a metrics-driven system – will only exacerbate this problem. If policy makers want scientists to engage with the public, something needs to be done about these systematic structural disincentives.

I’d like to move on to the more general question of the way policy has evolved in this sphere in connection with nanotechnology. To be blunt, the story here is of an opportunity presented to the UK to take a world lead, an opportunity that has been allowed to trickle away.

The Royal Society/ Royal Academy of Engineering report, published in the summer of 2004, was widely welcomed both in the UK and abroad. It made some very definite recommendations; here I’ll concentrate on three issues. On the possibility of the toxicity of some nanoparticles, the report recommended the setting up and funding of a centre for nanotoxicology studies. Similarly, on issues surrounding the more general relationships between nanotechnology and society, the report recommended funding a centre. Finally, the report recommended a well funded and coordinated program of public engagement. I think many of us were profoundly disappointed by the government’s response to this report, published in spring of last year, which simply rejected the first two of these recommendations.

Let me take the nanotoxicity issue first, as this is proving a case study in how to make a relatively small and manageable problem much bigger than necessary. “Is it safe?’ is the first question that the public, journalists or anyone asks about new products and new processes. It’s not a profound problem, but it needs an evidence base to answer. The report published by the Nanotechnology Research Coordination Group last autumn was in many ways a very good document, with a very good overview of the knowledge gaps and the research needed to fill them. The problem was that it simply failed to provide a mechanism to fill those gaps, simply hoping that good proposals would come to the research councils for funding by peer review. This seems to me to be a category error – the science we need to underpin regulation isn’t necessarily good science as defined by peer review, and if the capacity to do the research isn’t there one can’t just expect it to appear spontaneously.

On the broader relationships between nanotechnology and society, the story is similarly depressing. In the presence of so many excellent social scientists, I’ll not rehearse all the arguments for why these kinds of studies are a good idea, but I would like to pick up two important aspects. We’ll come to public engagement in a moment, but one thing my experience so far tells me is that debates about the impact of nanotechnology need to be informed by clear thinking about plausible possible futures, thinking that needs to be underpinned both by accurate science and an understanding of society and economics that goes beyond the naiveity displayed by a lot of futurism. The second point I’d make is that currently government is spending very large sums of money in an attempt to realise economic gains from its science investment. This spending is informed by tacit or explicit models of innovation, but are these models being critically tested? As we see focused and well resourced centres being set up to study these issues in the USA and in the rest of the Europe, in the UK we have a handful of excellent but small-scale projects, but no centre, no ear-marked funding, no coordination.

Public engagement is perhaps the one area where the picture is not so bleak, and in which the UK has taken a lead. A number of significant efforts, some government funded through schemes like Sciencewise, some, like Nanojury UK, initiatives from outside government, have been carried out. The government’s draft public engagement strategy – published last summer – sets out an overall framework, and a body – the Nanotechnology Engagement Group (which I chair) – has been charged with coordinating and disseminating good practise across government departments and agencies. The challenge now is designing institutional structures so that policy making really is informed by all this public engagement activity. In the key spending organisations – the research councils, led by EPSRC, in what used until recently to be the Innovation Directorate of the DTI, and in the MNT program, I don’t yet see those institutional structures in place.

In EPSRC, there are promising developments in the shape of the new committee chaired by Lord Winston set up to advise Council on public engagement issues. But, in the sphere of nanotechnology, the problem is that there isn’t actually a nanotechnology program for insights from public engagement to shape. The strategy of EPSRC with respect to nanotechnology has been, in essence, not to have a strategy. Has this worked? There are real concerns that the UK is not doing well in nanoscience and nanotechnology. A pair of international studies, commissioned by EPSRC, tell a depressing story. Most recently, we’ve had the report “International Perceptions of UK Research in Physics and Astronomy 2005”, which said “One particular area still requiring attention is nanoscience – it has become a very large area of emphasis worldwide, yet the UK lacks coherence and international visibility in the field.” A similar review for chemistry a few years ago told a similar story: “Nanoscience and technology in the UK clearly lags…It is, however, an area that requires seamless integration of electrical engineering, applied physics, chemistry, and mechanical engineering, and access to specialised facilities: it thus represents the type of multicentre, multidiscipline research at which the UK is constitutively weak. “ Recognising this weakness, EPSRC has set up a working party to consider a new strategy, which will report his autumn, but I’m left with the worry that there is a real structural problem emerging here.

Another point of view might be that what’s important here is that we succeed in making money from nanotechnology, and these societal and public engagement issues are just a distraction from this economic imperative. Clearly the government takes the innovation agenda extremely very seriously, but I would argue that it is a very serious mistake to suppose that the innovation agenda can be isolated from these societal issues. The most obvious connection is, of course, that the public that we’re engaging with is the very same public that will be the customers for the nano-enabled products we’re hoping for, and if they don’t buy the products then no-one will make any money. We hear frequent references to the sorry saga of agricultural biotechnology. A less obvious connection is stressed by my colleague Stephen Wood. It is also the public, working in the many economic sectors that will be affected by nanotechnology, all the way from directly science-based industries to all the areas in which the products of nanotechnology might be put into use, who will, by embracing or failing to embrace nano-enabled products and processes in their working practises, determine their economic impact. In any case I’d prefer to put the issue in a positive way – in our system, societal needs and desires are delivered through market mechanisms, so achieving consensus on what society wants from nanotechnology will as a by-product lead to the desired economic gains.

It’s worth taking a look at the history of the UK’s programme for promoting the commercialisation of nanotechnology. Again, this features a report with strong recommendations that were not followed. The 2002 Taylor report advised the immediate establishment of at least two National Nanotechnology Fabrication Centres. The government instead chose to implement a distributed, network, approach – the Micro- and Nano- Technology Initiative. Is this working? It’s probably too early to judge the economic impact directly, but again we can look at the perceptions of those from abroad. In September 2005 The US based consultancy LUX research published “Ranking the Nations: Nanotech’s Shifting Global Leaders.” This ranked the UK 12th out of 14th by measures of “Technology Development Strength”, not just behind Japan, the USA and South Korea, but behind France, Australia and Russia, and leading only India and China. One can argue, of course, about the validity and robustness of these measures, but these perceptions have a way of becoming self-fulfilling prophecies, as inward investment decisions are made on the basis of this kind of reports.

I’ve deliberately widened my discussion beyond public engagement and societal issues, because I think there is a depressing pattern emerging – a pattern of lack of commitment, institutional fragmentation, and a tendency to diffuse and unfocused efforts, which gives rise to the perception from outside the UK of a fundamental lack of seriousness.

One might ask why this matters. My answer isn’t so much that I believe that nanotechnology will soon be a one trillion dollar industry or will revolutionise this or that aspect of society. What’s more important is that nanotechnology is a test case for a new kind of science, fundamentally interdisciplinary, motivated by applications. How do we arrange to do goal-oriented science that delivers societal needs via market mechanisms with the broad support and consent of the population? This to me is the central question that underlies “Governing at the Nanoscale”.

The Nottingham nanotechnology debate – transcript now available

Last summer, a debate was held at Nottingham in which proponents and sceptics of the Drexlerian vision of molecular nanotechnology exchanged views (with me in the latter camp). I think it was notable both for its constructive tone, and for the high quality of the debate, helped by the presence of many very distinguished UK nanoscientists in the audience. At the time it was promised that a film of the event and a transcript would be published. These things often take longer than expected to come to fruition, but Philip Moriarty now reports, via a comment here, that the transcript, published in the journal Nanotechnology Perceptions, is now available for download from the Nottingham Nanoscience Group’s webpages. Since the links themselves are a bit obscure, the PDF of the transcript is here, and a short introductory piece by Philip is here.

To quote Philip Moriarty’s words: “The transcript on the following pages is the first time that a public (and lengthy) debate on the feasibility of nanomachines and molecular manufacturing, involving a significant number of world-leading surface- and nano-scientists, has been published in its entirety in the scientific literature.”