Kurser

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Blok 3 - 2011

Kurset handler om magnetisme, hvordan denne virker inden i materialer, og hvordan bl.a. magneter og typiske instrumenter der undersøger magnetisering fungerer.

Kurset får en bedømmelse på 4 ud af 5 stjerner, da det var et rigtig spændende og relevant kursus. Jeg blev dog nødt til at bruge uforholdsmæssigt lang tid på at læse til eksamen, da jeg synes at mange af emnerne var meget svære.

Jeg har lavet en formelsamling til dette fag. Denne kan hentes her på hjemmesiden under Formelsamlinger.

Magnetisme og magnetiske materialer kursusbeskrivelse

I kurset lærer vi om hvordan magnetisme fungerer i faste stoffer, og hvad det bruges til. Der blev brugt rigtig mange forskellige læsematerialer fra mange forskellige kilder i kurset, og de er alle oplistet nedenfor:

S. Blundell: Magnetism in condensed matter
Cathrine Frandsen: Note om Magnetiske Nanopartikler (2010)
Kim Lefmann: Note om neutronspredning
Cathrine Frandsen: Mössbauer spectroscopy and its application to studies of magnetic nanoparticles (2010)
Note om Magnetic Force Microscopy (kopi fra ukendt bog)
Rafal E. Dunin-Borkowski et al: Off-Axis Electron Holography of Magnetic Nanowires and Chains, Rings, and Planar Arrays of Magnetic Nanoparticles, Microscopy Research and Technique 64:390–402 (2004)
Roger Wood: Future hard disk drive systems (Journal of Magnetism and Magnetic Materials 321 (2009) 555–561)
Dele af: R. Lawrence Comstock: Introduction to Magnetism and Magnetic Recording (Wiley)
Dele af: Ian P. Jones: Materials Science for Electrical and Electronic Engineers (Oxford University Press)

Videre blev der til regneøvelserne i den første del af kurset brugt et sæt af ekstra opgaver. Disse kan hentes nedenfor:

Hent opgaver
Besvarelser fra uge 1 (S1.1, S1.2, B1.11, B1.12, B2.1, B2.2, B2.4)
Besvarelser fra uge 2 (S2.1, B3.1, S3.1, B4.2, B4.3, B4.4, B4.5)
Besvarelser fra uge 3 (B5.1, B5.4, B5.7, S5.2)
Besvarelser fra uge 5 (B6.1, B6.5, B5.8)
Besvarelser fra uge 6 (S13.2)

En oversigt over hvad vi lavede i kurset kan ses i tabellen nedenfor. Alle slides brugt under undervisningen kan også hentes her.

Uge	Dag	Pensum	Opgaver
1	Tirsdag	Introduction to the course, teachers and evaluation form. The absence of magnetic materials in classical physics (Bohr-van Leuven theorem), the atomic origin of magnetic moments, quantum mechanics of spin.: Blundell Ch. 1 except 1.1.4 (slides)	S1.1, S1.2, B1.1, (B1.11, B1.12)
	Fredag	Intro. stat. mech. + quantum mech., diamagnetism, paramagnetism, spin, orbital angular momentum, Hund's rules: Blundell 1.2.1 (p. 7), Ch. 2 (pp. 18-36), Appendix E, parts of Appendix C (slides)	S2.1, B2.4, (B2.2)
2	Tirsdag	Crystal field splitting, orbital quenching, Jahn-Teller effect: Blundell Ch. 3 (pp. 45-52), notes (slides)	S2.1, S3.1, (B3.1)
	Fredag	Exchange interactions, magnetic order: Blundell Ch. 4-5 (pp. 74-89) (slides)	B4.2, B4.3, B4.4, B4.5
3	Tirsdag	Mean-field theory, ferromagnetism, antiferromagnetism, helical structures: Blundell Ch. 5 (pp. 89-102) (slides)	B5.4, B5.7, S5.2, (B5.1)
	Fredag	Domains, shape anisotropy, Brown's equations, energy landscape, magnetic phase diagrams (slides)	B5.4, B5.7, S5.2, (B5.1)
4	Tirsdag	LLG-based micromagnetic simulations (slides)	Alternative exercises by MB (OOMMF exercises)
	Fredag	Macroscopic magnets in daily life, magnetic toys (slides)	Alternative exercises by MB (fun with magnets)
5	Tirsdag	Concepts of broken symmetry + Goldstone modes, phase transitions (very brief), spin-wave excitations: Blundell Ch. 6 (pp. 111-127)	B6.1, B6.5
	Fredag	Types of magnetic order and excitation, measurements of order and excitation by neutron scattering: Blundell Ch 5.7.2, 6.6.4 (103-108, 126-127) + notes on neutron scattering	B5.8, assignment, catch up
6	Tirsdag	Mössbauer spectroscopy and the magnetic properties of nanoparticles: Blundell 2.8, p.40-43, Blundell 3.2.3, p.65-68, Blundell 5.7.3. only the first 8 lines, Blundell 8.3, p. 170-171, Note on Magnetic nanoparticles	Problem with Mössbauer spectroscopy (link)
	Fredag	Magnetic Nanoparticles II: p 3-5 in the Note on Magnetic Nanoparticles
7	Tirsdag	Magnetic hysteresis, magnetic measurements and magnetic data storage: Comstock, pp. 19-21, 24-28, 52-56, Jones, pp. 264-282 (slides 1, slides 2)	Problem with hysteresis (link)
	Fredag	Magnetic imaging techniques: Mainly, magnetic force microscopy, and electron holography: Note on magnetic force microscopy, note on electron holography (slides)	Problem on Electron Holography (link)
8	Tirsdag	Magnetism in metals
	Fredag	Question session

Eksamensspørgsmålene i kurset endte med at blive som følger (de fleste af dem med både en teoretisk og en eksperimentel del, men nogle af dem kun med en teoretisk del):

Isolated magnetic moments (Blundell Ch. 2, p.18-36)
Mössbauer spectroscopy (Blundell 2.8 p. 40 + 3.2.3, OR CF-Note on Mössbauer spectroscopy p. 1-11)
Crystal fields (Blundell Ch. 3, p. 45-52)
Magnetic interactions (Blundell Ch. 4, p.74-83 (except 4.2.6), Ch. 7 p.156-157+ Assignment 1)
Order and magnetic structures (Blundell Ch. 5, p. 85-100 + Assignment 2)
Neutron diffraction (KL-Note on neutron scattering p. 5-9 + p. 11-17 + p. 19-22 + optionally p. 29-38)
Broken symmetry and spin waves (Blundell Ch. 6 p. 111-125, Assignment 3)
Inelastic neutron scattering (KL-Note on neutron scattering p.5-9 + p.11-17 + p. 24-28 + optionally p. 29-38)
Magnetic domain theory and hysteresis (Blundell Ch. 6 p. 127-136)
Magnetic force microscopy and electron holography (CF-Note on magnetic force microscopy p. 51-62 + Note on electron holography (Dunin-Borkowski et al. p. 390-402))
Magnetic nanoparticles (CF-Note on Magnetic Nanoparticles)
Mössbauer spectroscopy and neutron scattering (CF-Note on Mössbauer spectroscopy and its application to studies of magnetic nanoparticles; KL-Note on neutron scattering, p. 5-9 + p. 11-17 + p. 19-20 + Problem 13.2 + optionally p. 29-34)