This is NOT the question or not Everything
- Slides: 61
This is NOT the question or not ?
Everything is magnetic … How ?
macroscopic world meter … mole … 10+23 atomic or molecular world « wonder » world nano meter … 1 / 1 000 000 = 10 -9 molecule … 1
macroscopic world atomic or molecular world « wonder » world Lewis Carroll, Through the looking-glass, Penguin Books, London, 1998 Illustrations by John Tenniel
macroscopic world macro atomic or molecular world « wonder » world quantum
macroscopic world « traditional, classical » magnets N S macro
macroscopic world A pioneering experiment by M. Faraday « Farady lines of forces » about magnetic flux N S macro Courtesy Prof. Peter Day, the RI ; See also : The Philosopher’s Tree, The Institute of Physics Publishing, Bristol, 1999)
Courtesy Prof. Frank James, the RI
M. Faraday’s magnetic laboratory Courtesy Prof. Frank James, the RI
M. Faraday in his laboratory Courtesy Prof. Frank James, the RI
macroscopic world « traditional » magnets N N S S attraction N macro S N S
macroscopic world « traditional » magnets S N repulsion macro N N S S
macroscopic world looking closer to the magnetic domains N S macro many sets of domains many sets of atomic magnetic moments quantum
Physics : Macroscopic permanent magnets micron particles multi - domain nucleation, propagation and annihilation of domain walls macro Mesoscopic nanoparticles Nanoscopic clusters single - domain uniform rotation curling molecular individual clusters spins magnetic moment quantum tunneling, quantization quantum interference quantum Wolfgang Wernsdorfer, Grenoble
“No ! no ! The adventures first” said the Gryphon in an impatient tone : “explanations take such a dreadful time. ” Lewis Carroll, Alice’s Adventures in Wonderland, Penguin Books, London, 1998 Illustrations by John Tenniel
Everyday life is full of useful magnets which traditionally take the form of three-dimensional solids, oxides, metals and alloys macro Magnets Domains Curie Temperature
The magnetic moments order at Curie temperature A set of molecules / atoms : TC k. T ≈ J Magnetic Order Temperature Solid, Magnetically Ordered or Curie thermal agitation (k. T) weaker Temperature than the interaction (J) between molecules k. T << J … Paramagnetic solid : thermal agitation (k. T) larger than the interaction (J) between molecules k. T >> J
Magnetic Order : ferro-, antiferro- and ferri-magnetism Ferromagnetism : Magnetic moments are identical and parallel + = Ferrimagnetism (Néel) : Magnetic moments are different and anti parallel Antiferromagnetism : Magnetic moments are identical and anti parallel + = 0 + =
Magnetization of nanoparticles of Prussian Blue analogues, Micro. SQUID, 4 K (A. Bleuzen, W. Werndorfer)
Magnetization of nanoparticles of Prussian Blue analogues, Micro. SQUID, 4 K Remnant magnetization Coercive Field (A. Bleuzen, W. Werndorfer)
« He seemed to give off a radiance, an inner fire, and I couln’t resist this magnetism Fernande Olivier, Loving Picasso, H. N. Abrams Publishers, New York, 2001, p. 139
How magnetism comes to molecules ? … the different faces of the electron
Origin of Magnetism … the electron * I am an electron • rest mass me, • charge e-, • magnetic moment µB quantum everything, tiny, elementary * but do not forget nuclear magnetism !
Origin of Magnetism « Orbital » magnetic moment « Intrinsic » magnetic moment µorbital due to the spin s = ± 1/2 eµorbital = gl x µB x µspin = gs x µB x s ≈ µB quantum µtotal = µorbital + µspin
Origin of Magnetism … in molecules electrons * in atoms in molecules quantum * forgetting the nuclear magnetism
Dirac Equation The Principles of Quantum Mechanics, 1930 1905 Nobel Prize 1933 1928 http: //www-history. mcs. st-and. ac. uk/history/Pict. Display/Dirac. html
Representations, Models, Analogies … “When I use a word”, Humpty Dumpty said, … “it just means what I choose it to mean – neither more nor less “ “The question is”, said Alice, whether you can make words mean so different things” “The question is”, said Humpty Dumpty, “which is to be master – that's all. ” Lewis Carroll, Through the Looking-Glass, Penguin Books, London, 1998 Illustrations by John Tenniel
Electron : corpuscle and wave Wave function or « orbital » n, l, ml … l = 0 s 1 2 p d angular representation 3
Electron : also an energy level Orbitals Energy Diagramme Vacant Singly occupied Doubly occupied
Electron : also a spin ! Up Down Singly occupied « Paramagnetic » S = ± 1/2 Nitrogen Monoxyde NO • Doubly occupied « Diamagnetic » S = 0 Nitronylnitroxyde
Analogy : Spin and Arrow Paul Klee, Théorie de l’art, Denoël, Paris An Isolated Spin
Spin in Maya World ? Uxmal, Palacio del Gobernador, Mayab, Yucatan, July 2004
Molecules are most often regarded as isolated, non magnetic, creatures Dihydrogen diamagnetic Spin S = 0
the dioxygen that we continuously breathe is a magnetic molecule orthogonal π molecular orbitals paramagnetic, spin S =1 Two of its electrons have parallel magnetic moments that shapes aerobic life and allows our existence as human beings
when dioxygen is in an excited state it can becomes a singlet (spin S=0) and strange reactivity appears sometines useful (glow-worm …) macro Paramagnetic O 2 Luminol Light
More complex molecular frameworks called metal complexes built from transition metal and molecules are able to bear up to five or seven electrons with aligned magnetic moments (spins)
Transition Elements quantum
Mononuclear complex ML 6 Splitting of the energy levels E
How large is the splitting ? Weak Field High spin L = H 2 O [C 2 O 4]2 - Intermediate Field Strong Field Temperature Dependent Spin Cross-Over Low spin L = CN-
The complexes of transition metal present often delicate and beautiful colours depending mostly on the splitting of the d orbitals h macro Colours in water Geometry changes Spin changes
story of jumping electrons and moving spins …
two blue solutions
[Co. II(H 2 O)6]2+ + Methylene Blue KCN + Methylene Blue
one yellow solution
blue + blue = yellow ! [Co. III(CN)6]3+ Methylene Reduced Colorless
[Fe. II(H 2 O)6]2+ pale green S=2 Fe. II(o-Phen)3]2+ bright red S=0
Low spin, chiral, Fe. II(bipyridine)3]2+
Playing with ligands, the chemist is able to control the spin state
Review by Philipp Gütlich et al. Mainz University Angewandte Chemie 1994
Spin Cross-Over A Fe(II) « Chain » with spin cross-over R R N N N N Fe N N N N Fe R N N Fe N N N 4+ N N R R Triazole substituted Ligand (R) ; insulated by counter-anions Many groups : Leiden, Mainz, Kojima, O. Kahn, C. Jay, Y. Garcia, ICMC Bordeaux
Curie Law MT = Constant MT ≈ n (n+2) /8 … if n = 4, MT ≈ 3 !
Spin Cross-Over Bistability Domain Room Temperature 3 Red 0 The system « remembers » its thermal past ! O. Kahn, C. Jay and ICMC Bordeaux
Hysteresis allows bistability of the system and use in display, memories … macro Spin and colour changes
Spin Cross-over (1) Display Device (2) Joule and Peltier Connections Elements Compound in Low spin state (Thin Layer) (3) Display O. Kahn, J. Kröber, C. Jay Adv. Mater. 1992, 718 Kahn O. , La Recherche, 1994, 163
From the molecule to the material and to the device … O. Kahn, C. Jay and ICMC Bordeaux
Red White From J. F. Letard, ICMC Bordeaux
O. Kahn, Y. Garcia, Patent
May we go further and dream of molecular magnets i. e. low density, biocompatible transparent or colourful magnets ?
- What is a level 2 question
- ______ she beautiful?
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- Tag question everything
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- Not everything that counts can be counted meaning
- Question without question words
- Closed question
- Contoh open-ended question
- Examples of researchable and non researchable questions
- Examples of indirect questions
- Compelling and supporting questions
- Compelling and supporting questions
- Sadlier vocabulary workshop level d unit 1 synonyms
- Hát kết hợp bộ gõ cơ thể
- Ng-html
- Bổ thể
- Tỉ lệ cơ thể trẻ em
- Chó sói
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- Thế nào là hệ số cao nhất
- Các châu lục và đại dương trên thế giới
- Cong thức tính động năng
- Trời xanh đây là của chúng ta thể thơ
- Mật thư anh em như thể tay chân
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- Thế nào là sự mỏi cơ
- đặc điểm cơ thể của người tối cổ
- V. c c
- Vẽ hình chiếu đứng bằng cạnh của vật thể
- Fecboak
- Thẻ vin
- đại từ thay thế
- điện thế nghỉ
- Tư thế ngồi viết
- Diễn thế sinh thái là
- Các loại đột biến cấu trúc nhiễm sắc thể
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- Tư thế ngồi viết
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- Thiếu nhi thế giới liên hoan
- ưu thế lai là gì
- Khi nào hổ mẹ dạy hổ con săn mồi
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- Hệ hô hấp
- Từ ngữ thể hiện lòng nhân hậu
- Thế nào là mạng điện lắp đặt kiểu nổi
- Unlike routine claims, persuasive claims:
- You are aren't you
- Everything around us is called
- Lord i lift everything to you
- Resurrection changes everything