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MÖSSBAUER ANALYSIS OF THE ATOMIC AND MAGNETIC STRUCTURE OF ALLOYS i ii MÖSSBAUER ANALYSIS OF THE ATOMIC AND MAGNETIC STRUCTURE OF ALLOYS V.V. Ovchinnikov CAMBRIDGE INTERNATIONAL SCIENCE PUBLISHING iii Published by Cambridge International Science Publishing 7 Meadow Walk, Great Abington, Cambridge CB1 6AZ, UK http://www.cisp-publishing.com Translation from Russian of V.V. Ovchinnikov ‘Messbauerovskie metody analiza atomnoi i magnitnoi struktury splavov. Fizmatlit, Moscow, 2002, (ISBN 5-9221-0259-1) English translation published November 2006 © V V Ovchinnikov © Cambridge International Science Publishing Conditions of sale All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 10: 1-904602-13-4 ISBN 13: 978-1-904602-13-2 Cover design Terry Callanan Printed and bound in the UK by Lightning Source (UK) Ltd iv . Preface I am pleased to welcome English-language readers and I would like to say several words about why I have written this book. Undoubtedly, the Mössbauer effect in the period since its discovery has acquired a position as one of the most informative methods of examination of the atomic and magnetic structure of solids. However, of the large number of original publications, it is relatively difficult to extract fundamental principles representing the basis of these investigations. This must be carried out using several generalisations, and I have undertaken this task. I regarded it as necessary because it is clearly evident that the discovery of the Mössbauer effect has indicated a number of completely new possibilities in the examination of the atomic and magnetic structure of solids, in comparison with the possibilities provided by the conventional methods. I participated in the development of non-diffraction Mössbauer methods of analysis of the atomic and magnetic structure of alloys [31,59,63,138,139,213 – FMM (Rus), 203,204, 330 – FTT, Pis’ma JTF (Rus), 68, 427 (Engl), and others], representing an alternative to the conventional methods based on the diffraction phenomenon (x-ray, electron and neutron). However, the above studies, published mainly in Russian journals, are usually not known to foreign readers. The justification of the Mössbauer methods of the analysis of the atomic and magnetic structure of alloys required analysis of the problems associated with the listing of different non-equivalent positions of resonant nuclei (atoms) in these systems. In addition to this, it was necessary to develop methods of the analytical description of the probabilities of appropriate positions, in relation to the condition of the investigated objects (with rational restriction of the radius within which the differences in the interactions are taken into account). The probabilities of the positions specify the relative intensities of ‘sub-spectra’ which form the Mössbauer spectrum. Their number for alloys with a variable composition, including multiphase alloys, with imperfect long- and short-range great atomic and magnetic orders, and also of multilayered superlattices, is relatively large. Finally, it was necessary to v describe the electrical and magnetic superfine interactions of resonant nuclei in the investigated positions (in the presence of atoms of different type in several closest coordination spheres of these nuclei) which determine the position of the individual lines in the composition of the sub-spectra. The conclusions of the current theory of the interpretation of the results