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Submitted on 1 Jan 1980
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CONCLUDING REMARKS
H. de Waard
To cite this version:
H. de Waard. CONCLUDING REMARKS. Journal de Physique Colloques, 1980, 41 (C1), pp.C1-
497-C1-499. �10.1051/jphyscol:19801197�. �jpa-00219687�
JOURNAL DE PHYSIQUE Colloque C1, suppl4ment au n " 1, Tome 41, janvier 1980, page C1-497
CONCLUDING R W K S
H. de Waard
Laboratoriwn voor Algemeine Natuurkunde, University, Groningen, Netherlands.
A conference summarizer who knows that he has to perform his task from the start of the conference is a privileged person, because he is morally obliged to attend as many lectures and view as many posters as possible. Thus he may learn more than the other participants. But he is also a trou- bled person because, having done so, the large variety of impressions makes it diffi- cult to obtain a clear overview.
Yet I will try to point out some high- lights, to draw some conclusions about the usefulness as well as the shortcomings of this conference and to make some recommen- dations for future conferences.
MiSssbauer spectroscopy continues to contribute to our understanding of a varie- ty of problems, both of fundamental and applied character, in the natural sciences.
In particular I would like to mention the following :
affairs appears to have improved. Several really important applications have been brought forward at this conferende.
I mention :
- -
Sen&o~dgctog Lmpl~ntatign~ It is surpri- sing that, while implantation of semiconduc- tor devices-
especially field effecttransistors
-
has given a very substantial contribution to the development of transistors with very low power consumption, so little is known' about the exact location of the implanted impurities. MiSssbauer sprctroscopy combined with channeling offers interesting possibilities to ledrn more, gb-out .th.$~';. B'Shas been demonstrated by the work of the Leuven and Groningen groups.
-
gngrphgus metals,
where conclusions about geometrical structure and electronic bonds have been drawn from Msssbauer spectra..Technical applications of such metals look very promising now and are rapidly increasing 1.- Magnetism. Both the present conference in
-
and the preceeding International Conference --S~rfa~e-cgr~O~i?n, as reviewed Meisel on Magnetism clearly establi,sh the role of 1/, continues to attract attention. Gfltlich mssbauer
s p e ~ t ~ g a a a p y
k4 @$ping tocia^
2/ demwstrated hpw depth selective conver-;ify the'magnetiC- structure of many magfletic sion MiSssbauer using compounds. Recent&, a trend to micromagne- a chanfihltron for electron detection iian be tism can be
observedr
bobh as regardg the applied to routine investigatioris of the magnetism of compounds characteri.zed by corxosian of steei pipes used in the pdwcr one and two dimensional magnetic structures industry 'and as regards magnetism of extremely thin 3.-The importance of using complementary layers. Art Freeman reported on recent methods for investigating solid state pro- calculations for the latter systems and we perties has, of course, been always advoca- are eagerly looking forward for a detailed ted but not always fully exploited. It is, paper on this subject. therefore, gratifying to see that Mbssbauer
2 . - Useful a lications. It has long b- spectroscopists are increasingly using other
a matter of good policy to.advertize. techniques. Some of these exploit the hyper- MiSssbauer spectsosc~py as-) eukeful t(7p.-p+ @ ~ $ . ~ ~ I ~ i t e r a c t i o n and, like Mtjssbauer spec- technomy, f.&: c&6gj gf where
ci #
. t3$?sC6&.,, are resonance methods : NMR and~ n . 1 , ~ of,
r n a f g h i i
tfti'Lti'e,$as
state of ESR h$LW been with us a long time and,Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19801197
C1-498 JOURNAL DE PHYSIQUE
through their superior spectral resolution patterne of a carrier filtered Plassbauer have outperformed Mdssbauer spectroscopy in
a number of cases. The "nuclear" hyperfine interaction techniques of time differential perturbed angular correlation and NMR on oriented nuclei are also increasingly ap- plied. They also give a higher resolution in certain cases and thus a clearer insight.
A very special role in magnetic studies has further been played by muon spin rotation for the last few years.
Among the non-nuclear methods, Ruther- ford back scattering, including channeling continues to provide useful complementary information on the structure of surface layers and on impurity location in such layers. Relatively recent additions to the list of methods combined with Mbssbauer spectroscopy are x-ray induced photoelec- tron spectroscopy (XPS) and the extended fine structure of x-ray absorption edges
spectrum, as devised by Perlow, Potzel and Monahan /7/ certainly constitutes a new and valuable addition to Mdssbauer methodology.
It deserves application to other isotopes than 5 7 ~ e .
-
Fitzsimmons work /8/ on anisotropic rela- xation into rotational degrees of freedom forms a particularly well documented set of investigations with novel results.-
Finally, I would like to mention the use of P~-CO(~'CO) alloys with giant cobalt moments as probes for the magnetic field of an extended superconductor by Dean Taylor /9/; a quite sophisticated application.In Bendor (1974) I pointed out that filassbauer spectroscopy had further shifted to the exclusive use of 5 7 ~ e : 76% of all papers presented there compared to 67% in Aveleth Hashahar
-
(1972) dealt with that isotope. At the present conference I coun- (EXAFS) as reviewed by Chappert / 3 / . ted 200 papers on 5 7 ~ e spectroscopy, 48 onAfter these remarks on more general
all other isotopes together, which means highlights of the conference I would like
another increase of 57Fe papers : to sl%.
to mention a small number of papers that
I believe that my remark at Bendor should appeared to me as novel and interesting,
be repeated : other isotopes than 5 7 ~ e also with immediate apologies for incompleteness
lend themselves to the solution of interes- and a subjective bias.
ting problems !
-
I think that everyone agrees that Richard -Frankels /4/ very nice research on magnetic The diversity of the subjects covered bacteria deserves the first place in this at Mdssbauer conference such as this one is
brief list. regarded by some participants as a draw-
-
What may prove to be another quite inte- back, by others as a special good quality.resting development is the use of anti- Personally I feel that learning about reflecting layers for filtering synchrotron subjects outside ones own specially is very
important for the conception of new ideas :
radiation. If successful, this work of Hannon et al. /5/ should provide us with monochromatic electromagnetic radiation for use as a Mdssbauer source of unprecedented intensity.
-
Mdssbauer emission spectroscopy of chemi- cal compounds has been used to investigate relaxation processes that occur after nuclear decay. Vitalii Goldanskii /6/ has explained to us how the measurement of such processes as a function of temperature may yield information about the interesting phenomena of electron and nuclear tunneling.-
The determination of very small line shifts from the side band interferencephysics often progresses by association of bits of knowledge from very different parts Our series of Mdssbauer conferences is uni- que in this respect. It is clear, however, that there should also be topical conferen- ces, concentrating on 'one special object.
It would be easy, of course, to go to so many conferences that no time is left for ones own work. Therefore, the decision to reduce the Mtjssbauer conference frequency to 0.5 y-l appears to be appropriate.
The diversity of subjects has led to a rather high degree of incoherency of the sessions. Many of the invited talks had
little connection with contributed papers presented during the same session and these papers among themselves more often than not were also unrelated. This state of affairs is inherent in this type of conference.
Once accepted as a fact, it leads to inte- resting thoughts about alternative ways of programming a conference. May I invite you to indulge for a few moments in one possi- ble new concept in conference programming,
involving a quite different set of sessions:
1. Papers on work published some time ago
2. Papers on uninterpretable experi- mental results
3. Fapers on the theory of impossible experiments
4. Papers on proposed experiments 5. Contributed review papers 6. Uninvited papers
7. Papers on new and exciting results (according to the author)
8. Papers on new and exciting results (according to the program committee) 9. The empty poster session
This novel way of arranging the sessions has several clear advantages r
-
It offers more possibilities of join the a c c o m p a n y i n g p e r s o n s program without a bad conscience.-
It offers more time for tennis, swimming, boozing, etc.-
More time is available for private dis- cussions (probably on the subjects of sessions 1-4 and 7).of course, there will remain also non-empty poster sessions, and these should then really be called
full
sessiqns. I have a few specific suggestions for important improvements of such sessions :1. Use all available space on the poster board, especially near the floor. This necessitates visitor and showman to crouch close to each other and thus creates a t o g e t h e r n e s s i n a d i f f i c u l t s i t u a t i o n . 2. Do not exceed a letter size of 2 mm. ' This ensures a close contact of the au- dience with the showman's work and at the same time increases the volume of data that
can be presented on one poster.
3. Never define any of the quantities used in formulas. This provides the showman with a good opening gambit for discussions.
After these undoubtedly most valuable suggestions for the future let us return to the present. I am certain that every- body will agree with me that we have had a wonderful time here. The quality of a conference depends, apart from the contents of the papers and the posters, very much on smooth organization and on environmental conditions. Both have been excellent. We have to thank for this the efficient up- and downstairs secretaries who took such good care of us and who reminded us gently yet persistently of our duties. We must also thank our projectionist and our micro- phonists for their active but unobtrusive presence and their fast reactions to
sometimes unintelligible requests. The real success of this conference, however, has in large measure been the work of one
person : our incomparable Dr. Danica Hanzel.
She did everything and was everywhere. She found this beautiful and functional loca- tion and she composed a program that was well balanced between listening, viewing and talking both in its scientific and social parts. We are all deeply thankful to her for making this week so fruitful and enjoyable for us.
REFERENCES
/1/ W. Meisel, invited paper at this conference, p. C1-63
/2/ P. Gutlich, short communication during this conference.
/3/ J. Chappert, invited paper at this conference, p. C1-9
/4/ R.B. Frankel, communication during this conference.
/5/ J.P. Hannon et al., invited paper at this conference, p. C1-59
/6/ V.I. Goldanskii, invites paper at this conference, p. C1-43
/7/ G.J. Perlow et al. invited paper at this conference, p. C1-85
/8/ B.W. Fitzsimmons, invited paper at this conference, p. C1-33
/9/ R.D. Taylor and J.O. Willis, contributed paper at Chis conference, p. C1- 211
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