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NEUTRON REFLECTOMETRY: a PROBE for MATERIALS SURFACES the Following States Are Members of the International Atomic Energy Agency 1HXWURQ5HIOHFWRPHWU\ $3UREHIRU0DWHULDOV6XUIDFHV 3URFHHGLQJVRID7HFKQLFDO0HHWLQJ 9LHQQD±$XJXVW NEUTRON REFLECTOMETRY: A PROBE FOR MATERIALS SURFACES The following States are Members of the International Atomic Energy Agency: AFGHANISTAN GHANA PAKISTAN ALBANIA GREECE PANAMA ALGERIA GUATEMALA PARAGUAY ANGOLA HAITI PERU ARGENTINA HOLY SEE PHILIPPINES ARMENIA HONDURAS POLAND AUSTRALIA HUNGARY PORTUGAL AUSTRIA ICELAND QATAR AZERBAIJAN INDIA REPUBLIC OF MOLDOVA BANGLADESH INDONESIA ROMANIA BELARUS IRAN, ISLAMIC REPUBLIC OF RUSSIAN FEDERATION BELGIUM IRAQ SAUDI ARABIA BELIZE IRELAND SENEGAL BENIN ISRAEL SERBIA BOLIVIA ITALY SEYCHELLES BOSNIA AND HERZEGOVINA JAMAICA SIERRA LEONE BOTSWANA JAPAN SINGAPORE BRAZIL JORDAN SLOVAKIA BULGARIA KAZAKHSTAN SLOVENIA BURKINA FASO KENYA SOUTH AFRICA CAMEROON KOREA, REPUBLIC OF SPAIN CANADA KUWAIT SRI LANKA CENTRAL AFRICAN KYRGYZSTAN SUDAN REPUBLIC LATVIA SWEDEN CHAD LEBANON SWITZERLAND CHILE LIBERIA SYRIAN ARAB REPUBLIC CHINA LIBYAN ARAB JAMAHIRIYA TAJIKISTAN COLOMBIA LIECHTENSTEIN THAILAND COSTA RICA LITHUANIA THE FORMER YUGOSLAV CÔTE D’IVOIRE LUXEMBOURG REPUBLIC OF MACEDONIA CROATIA MADAGASCAR TUNISIA CUBA MALAYSIA CYPRUS MALI TURKEY CZECH REPUBLIC MALTA UGANDA DEMOCRATIC REPUBLIC MARSHALL ISLANDS UKRAINE OF THE CONGO MAURITANIA UNITED ARAB EMIRATES DENMARK MAURITIUS UNITED KINGDOM OF DOMINICAN REPUBLIC MEXICO GREAT BRITAIN AND ECUADOR MONACO NORTHERN IRELAND EGYPT MONGOLIA UNITED REPUBLIC EL SALVADOR MOROCCO OF TANZANIA ERITREA MYANMAR UNITED STATES OF AMERICA ESTONIA NAMIBIA URUGUAY ETHIOPIA NETHERLANDS UZBEKISTAN FINLAND NEW ZEALAND VENEZUELA FRANCE NICARAGUA VIETNAM GABON NIGER YEMEN GEORGIA NIGERIA ZAMBIA GERMANY NORWAY ZIMBABWE The Agency’s Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The Headquarters of the Agency are situated in Vienna. Its principal objective is “to accelerate and enlarge the contribution of atomic energy to peace, health and prosperity throughout the world’’. PROCEEDINGS SERIES NEUTRON REFLECTOMETRY: A PROBE FOR MATERIALS SURFACES PROCEEDINGS OF A TECHNICAL MEETING ORGANIZED BY THE INTERNATIONAL ATOMIC ENERGY AGENCY AND HELD IN VIENNA, 16–20 AUGUST 2004 INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 2006 COPYRIGHT NOTICE All IAEA scientific and technical publications are protected by the terms of the Universal Copyright Convention as adopted in 1952 (Berne) and as revised in 1972 (Paris). The copyright has since been extended by the World Intellectual Property Organization (Geneva) to include electronic and virtual intellectual property. Permission to use whole or parts of texts contained in IAEA publications in printed or electronic form must be obtained and is usually subject to royalty agreements. Proposals for non-commercial reproductions and translations are welcomed and will be considered on a case by case basis. Enquiries should be addressed by email to the Publishing Section, IAEA, at [email protected] or by post to: Sales and Promotion Unit, Publishing Section International Atomic Energy Agency Wagramer Strasse 5 P. O. B o x 1 0 0 A-1400 Vienna Austria fax: +43 1 2600 29302 tel.: +43 1 2600 22417 http://www.iaea.org/books © IAEA, 2006 Printed by the IAEA in Austria August 2006 STI/PUB/1246 IAEA Library Cataloguing in Publication Data Neutron reflectometry : a probe for materials surfaces : proceedings of a technical meeting / organized by the International Atomic Energy Agency and held in Vienna, 16-20 August 2004. — Vienna : The Agency, 2006. p. ; 24 cm. — (Proceedings series, ISSN 0074–1884) STI/PUB/1246 ISBN 92–0–103906–9 Includes bibliographical references. 1. Reflectometer — Congresses. 2. Neutrons — Congress. I. International Atomic Energy Agency. II. Series: Proceedings series (International Atomic Energy Agency). IAEAL 05–00447 FOREWORD Research reactors play an important role in delivering the benefits of nuclear science and technology. The IAEA, through its project on the effective utilization of research reactors, has been providing technical support to Member States and promotes activities related to specific applications. Neutron beam research is one of the main components in materials science studies. Neutron reflectometry is extremely useful for characterizing thin films and layered structures, polymers, oxide coatings on metals and biological membranes. The neutron has been a major probe for investigating magnetic materials. Development of magnetic multilayers is important for diverse applications in sensors, memory devices, etc. The special nature of the interaction of the neutron with matter makes it an important tool to locate low z elements in the presence of high z elements, which is useful in biology and polymer science. The role of neutron reflectometry in research and development in materials science and technology was discussed in a consultants meeting held in 2003. Following this, a technical meeting was organized from 16 to 20 August 2004 in Vienna to discuss the current status of neutron reflectometry, including the instrumentation, data acquisition, data analysis and applications. Experts in the field of neutron reflectometry presented their contributions, after which there was a brainstorming session on various aspects of the technique and its applications. This publication is the outcome of deliberations during the meeting and the presentations by the participants. This publication will be of use to scientists planning to develop a neutron reflectometer at research reactors. It will also help disseminate knowledge and information to material scientists, biologists and chemists working towards characterizing and developing new materials. The IAEA thanks all the experts for their active participation in the meeting, for the manuscripts of their presentations and for their contribution in preparing the summary. Thanks are also due to A.R.Wildes from the Institut Laue-Langevin, Grenoble, France, for his paper on polarized neutron reflectometry. The IAEA officer responsible for this publication was S.K. Paranjpe of the Division of Physical and Chemical Sciences. EDITORIAL NOTE These Proceedings have been edited by the editorial staff of the IAEA to the extent considered necessary for the reader’s assistance. The views expressed remain, however, the responsibility of the named authors or participants. In addition, the views are not necessarily those of the IAEA, the governments of the nominating Member States or the nominating organizations. The report does not address questions of responsibility, legal or otherwise, for acts or omissions on the part of any person. The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or recommendation on the part of the IAEA. The authors are responsible for having obtained the necessary permission for the IAEA to reproduce, translate or use material from sources already protected by copyrights. CONTENTS SUMMARY . 1 Principles of reflectometry with reactors and pulsed sources . 29 J. Penfold Specular neutron reflectivity: Applications to soft matter . 45 J. Penfold Design of a neutron reflectometry at a research reactor . 59 Z. Tun Polarized neutron reflectivity on D17 at the Institut Laue-Langevin . 69 R. Cubitt Oxide films and corrosion. 79 J.J. Noël Neutron reflection studies of solid–liquid interfaces. 85 A.R. Rennie Neutron reflectometry in Australia: Present and future. 95 A. Nelson, M. James, J.C. Schulz, A. Brule Development of a TOF reflectometer at the Greek Research Reactor . 103 K. Mergia, G. Apostolopoulos Neutron reflectometer at the Budapest research reactor with polarization option. 117 L. Cser Neutron reflectometry at Dhruva reactor: Specular and off-specular neutron reflectivity studies . 129 S. Basu, S. Singh Application of polarized neutron reflectometry . 145 A.R. Wildes n/X materials science reflectometer at FRM-II in Garching . 161 A. Rühm, U. Wildgruber, J. Franke, J. Major, H. Dosch Neutron specular reflectometry: Some aspects of theory. 177 H. Leeb List of Participants. 197 SUMMARY 1. REVIEW OF NEUTRON REFLECTOMETRY 1.1. Introduction Neutron reflectometry (NREF) is a relatively new technique that has widespread applications as a powerful analytical tool to analyse interfacial structure and composition. The recent upsurge in phenomena occurring over the nanometre scale and the unusual properties of low dimensional materials, compared with their bulk counterparts, are expected to yield a range of new products for electronics, photonics, etc. NREF is poised to help address the questions that will arise in the development of advanced thin film devices and functional interfaces of active materials with large surface areas. In its simplest form this technique measures the intensity of a specularly (angle of incidence = angle of reflection) reflected neutron beam as a function of wavelength and/or angle. If the thin film surface constitutes the (x, y) plane and the z axis is normal to the surface, then for specular reflectivity, momentum transfer Qx and Qy are zero and Qz is given by: QZ = ()()4plsin q (1) where λ is the wavelength of the incident neutron
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