B013457 - MAGNETIC MOLECULES

1) Magnetic interactions in molecular systems: single ion electronic levels, exchange and dipolar interaction, magnetic anisotropy. Spin Hamiltonian. Bistability and hysteresis in magnetic molecules. The process of inversion of the magnetization. Relaxation in the thermally activated and quantum tunneling regime. Perspectives and applications

Recommended reading:
-D. Gatteschi, R. Sessoli, J. Villain “Molecular nanomagnets”, Oxford University Press (2006)
-O. Kahn “Molecular Magnetism”, VCH (1993)
A copy of the slides can be downloaded from the web before the lectures

Knowledge acquired:
Basic electronic structure of metal ions in condensed matter. Spin Hamiltonian in magnetic molecules. Techniques for characterizing the magnetic properties. Origin of magnetic anisotropy, modeling and controlling the spin dynamics
Competence acquired:
Recording electron spin resonance spectra of molecular systems and their basic interpretation. Characterization and modelling of static and dynamic magnetic properties
Skills acquired (at the end of the course):
the student should be able to recognize the systems and/or situations in which the analysis of magnetic properties can provide additional information on their electronic structure. The student should also be able to choose the best suited investigation technique among those studied in the course

Courses recommended: Matter Physics

Total hours of the course (including the time spent in attending lectures, seminars, private study, examinations, etc...):

150
Hours reserved to private study and other individual formative activities:
90
Contact hours for: Lectures (hours): 45

Contact hours for: Laboratory (hours): 5
Contact hours for: Laboratory-field/practice (hours): 10

Frequency of lectures, practice and lab:
recommended

Teaching tools:
It is possible to take the exam by performing a short practice in the laboratory of magnetism
Office hours:
Every day, by fixing an appointment by phone or e-mail

Exam modality: It is suggested to perform a practical experience for one day to collect data. Their analysis is presented in a short written document and its discussion is done orally. Alternatively the exam consists in questions with answers given by word of mouth.

Part 1. Introduction (Prof. Gatteschi)
a) Magnetic interactions in molecular systems:
- electronic levels of the free ion
- group theory
- ligand field theory
b) The spin Hamiltonian formalism
- magnetic anisotropy
-exchange and dipolar interactions

Part 2 (Prof. Sessoli)
a) Investigation techniques in molecular magnetism
- dc magnetometry
- ac susceptometry
- electron paramagnetic resonance (EPR)
b) Magnetic bistability and hysteresis in molecular systems:
-Inversion of the magnetization
-Relaxation in the thermally activated regime
-Relaxation in the quantum tunnelling regime
-Molecular nanomagnets and magnetic nanoparticles: analogies and differences