Unit NANOMAGNETISM AND SPINTRONICS
- Course
- Physics
- Study-unit Code
- GP005936
- Curriculum
- Fisica della materia
- Teacher
- Giovanni Carlotti
- Teachers
-
- Giovanni Carlotti
- Hours
- 47 ore - Giovanni Carlotti
- CFU
- 6
- Course Regulation
- Coorte 2018
- Offered
- 2018/19
- Learning activities
- Affine/integrativa
- Area
- Attività formative affini o integrative
- Academic discipline
- FIS/03
- Type of study-unit
- Opzionale (Optional)
- Type of learning activities
- Attività formativa monodisciplinare
- Language of instruction
- Italian, but with references and textbooks in english
- Contents
- Physics of magnetism and magnetic materials, of nanometric systems. Basics of spintronics and magnonics. Applications to ICT devices.
- Reference texts
- Notes delivered by the teacher, integrated by selected parts of the following textbooks:
Ibach-Luth, SOlid State Physics (Springer);
N. Spaldin, Magnetic Materials (Cambridge);
J. Stohr-H.C. Siegman, Magnetism (Springer);
D. Stancel - A. Prabhakar, Spin Waves (Springer) - Educational objectives
- Comprehension of the physics of magnetic materials, with emphasis given to nanometric systems. Knowledge of the main experimental techniques and ability to perform micromagnetic simulations. Application to ICT devices.
- Prerequisites
- To achieve a satisfactory comprehension of the arguments of this course, it is necessary to know the basic elements of electromagnetism, condensed matter physics and quantum mechanics that are usually included in the background of the three-year Laurea degree in Physics.
- Teaching methods
- The course will mainly consist of face-to-face lessons. However, multimedia materials will be also shown and micromagnetic simulations will be performed to realize virtual experiments. Moreover, some lessons will be held in the Laboratory to show experimental techniques relative to the contents of the course.
- Learning verification modality
- Ora exam after the end of the course, whose duration will be about one hour. In the first part, the student will present a topic at his/her choice, with reference to his readings of specialised literature. In the second part, the teacher will propose several questions to verify the preparation of the student about the program covered during the course.
- Extended program
- 1) Introduction to the course. Basic definitions and outlook on applications. Relevant length- and time-scales. Survey about applications and theoretical approaches. Measurement systems. Recall about atomic magnetism and spin-orbit interaction. L-S and J-J coupling. Hund’s rules.
2) Classical theory of Diamagnetism and Paramagnetsim. Quantomechanical corrections. Pauli paramagnetsm and Pauli diamagnetism of free electrons. Ferromagnetic behaviour: classical theory of Weiss, molecular field and magnetic domains.
3) Exchange interaction and its quanto-mechanical origin. Helium atom. Ferromagnetism. Heisemberg hamiltonian. Temperature dependence of the magnetization. Exchange interaction between free electrons . Band model of ferromagnetism. Stoner criterion. Spin waves in the exchange regime.
4) Quantum theory of electrical conductin, electron motion and transport phenomena. Boltzmann equation and relaxation time. Two-currents model. Spin-dependent. Spin-dependent scattering and spin accumulation. Interlayer exchange coupling and giant magneto resistance. Tunnel magnetoresistance and its applications. Spin valve and magnetic memories. Spin-Hall effect. Spintronic devices.
5) Magnetic body: from macro- to nano-dimensions. Demagnetizing and stray field. Magnetic anisotropies. Energetic formulation. Micromagnetism. Numerical approach to the determination of the magnetic ground state. Stoner-Wolfhart model. Dynamic behavior: the Landau-Lifshitz-Gilbert equation. Damping. Dynamics of a nanodot. Spin-tranfer torque. Spin-torque oscillators.
6) Spin waves in thin films and multilayers. Dipolar-exchange regime. Magnonic crystals and magnonic devices. Excitation of spin waves by microstripes, coplanar waveguides, spin-torque or spin-Hall effect. Working principles of LEDs and LASERs. Optical techniques for the detection of spin waves. MagnetoOptical Kerr Effect and Brillouin light scattering.