Special courses for the students of Physics Faculty, specialized at the Department.

 

Introduction to Solid State Physics

32 hours, 6-th term

 

A basic introduction into the solid state physics is given. Physical principles of the existence of metallic, semiconductor and dielectric states are presented. A special emphasis is given to cooperative phenomena, magnetism and ferroelectricity. A review of characteristic ferroelectric and magnetic materials is given. General introduction into the localized and itinerant approaches in magnetism is given.

 

Physics of Ferroelectrics

36 hours, 7-th term.

 

The physical principles of ferroelectric phenomena in crystals on the base of modern theory of structural phase transitions and critical phenomena. The anomalies of physical properties in the phase transition in accordance with the crystal symmetry. The properties of proper, pseudoproper and improper ferroelectrics and related materials. The microscopic models for order-disorder and displacement ferroelectric phase transitions and the degree of their applicability to the real crystals.

 

Solid state physics

36 hours, 7-th term

 

This course gives the concise account of the essential elements of the solid state physics. The sequence of the presentation of the fundamental aspects of the solid state physics is realized according to the scheme: chemical bonding, structure, lattice dynamics and electronic properties. We believe that this sequence is the optimum choice for tutorial purposes. It enables the more difficult concepts to be introduced at a point where a basic understanding of fundamental ideas has already been achieved through the study of simple models and examples. Taking into consideration that in solid state physics the interaction between theory and experiment has always played a vital role, weˆà have attempted through this course to steer a middleˆà approach in which both theory and experiment are adequately represented.

 

Physics of magnetic phenomena

36 hours, 7-th term

Part 1. Weak magnetic substances

 

The fundamental characteristics of the magnetic state of matter,the magnetism of the elements of the Periodic Table, the behavior of atoms in the magnetic field. The systematics of types of magnetic order in solids. The systematic study of a weak-magnetic substances: diamagnetics and paramagnetics. Classical and quantum approaches to a diamagnetism. Comparison of experimental results with theory. The conduction electrons diamagnetism, the Landau levels, the oscillations of the magnetic susceptibility, the Pauli conduction electrons paramagnetism, the Van Vleck paramagnetism, and the paramagnetic susceptibility of the transition metals.

 

Physics of magnetic phenomena

36 hours, 8-th term

Part 2.The ehchange interactions in spin-ordered materials.

 

The description of the ferromagnetic state in the frame of molecular field approximation with the models of Weiss and Stoner. The magnetic phase transitions Landau theory for second order transitions. The theory of exchange interactions for two-electron systems in Heitler-London and molecular orbitals approximations. The direct exchange interactions for solid state materials in Heisenberg model and in the models of weak and strong interactions. The indirect exchange in Kramers-Anderson approximation for dielectrics and in Ruderman-Kittel-Kasuya-Yoshida (RKKY)-approximation for metals and alloys. The peculiarities of exchange interactions in amorphous spin-ordered materials.

 

Magnetism of nano-systems.

36 hours, 8-th term

 

This course is devoted to problems of nano-sized magnetism. It is assumed that student will get knowledge about magnetic properties of such systems as molecular, clusters, nano-particles, surfaces, ultra thin films, mono- and multilayers. Special attention will be paid to: technological methods of fabrication and experimental characterization of nano-structures (with simultaneous demonstration of about 10 techniques); correlation properties of nano-structures and their matrixes; valence of nano-structures; dependence of magnetic properties from dimensionality; opportunity of arising of magnetism (for dimensionality lowering) in nonmagnetic bulk materials. Few lectures will concern such perspectives of technical applications of nano-structured magnetic materials as nano-composite permanent magnets, nano-crystalline materials, magnetic and magneto-optical hard/removable disks, magneto-electronics, magnetic sensors etc.

 

Modern experimental methods in magnetic science

32 hours, 8-th term

 

The analysis of basic experimental methods for studies of the magnetic structures: a)investigations of macroscopic parameters (the methods for studies of average magnetic moments of atoms, magnetocrystalline anisotropy, magnetic phase transitions, spin reorientation transition); b)investigations of the microscopic parameters (the methods for studies of local magnetic moments of atoms: scattering of polarized neutron, nuclear magnetic resonance (NMR), nuclear spin echo method, Mossbauer effect,ˆà muon spin rotation (MSR)).

 

Magnetic ions in a crystalline electric field

32 hours, 8-th term

 

(Numerical calculations of the magnetic and magnetoelastic properties for 3d- and 4f ions in crystals)

The interaction hierarchy for the 3d- and 4f ions in a crystal. The formalisms of operator equivalents and tensor operators, the pseudospin formalism. The crystal field Hamiltonian for different crystal symmetries. The full Hamiltonian for a 4f paramagnet and various methods for defining its eigenvalues and eigenvectors. The perturbation theory and general initial susceptibilities. Numerical methods for defining of an electronic structure. Free energy and partition function and numerical calculation of the different thermodynamical properties for 3d- and 4f paramagnets. Magnetic susceptibility, magnetization, magnetic crystal anisotropy, energy level crossing. Magnetic energy, magnetic entropy, magnetic specific heat, magnetocaloric effect. Multipole moments of 4f ions and quadrupole approximation. Magnetostriction, magnetoelastic anomalies of the thermal expansion and elastic constants. Quadrupole moment ordering in the 3d and 4f magnets of the cubic and tetragonal symmetry. Examples of the numerical calculations of a 4f ion electronic structure and various magnetic and magnetoelastic properties in a cubic and tetragonal crystal field.

 

Paraprocess effects in ferro- and ferrimagnetics

36 hours, 7-th term

 

Paraprocess (true magnetization) has been thoroughly investigated around the Curie point region for a long time. The brightest appearance of the paraprocess and accompanying magnetostriction phenomena can be seen in invar-like alloys. Their study in these alloys allow to explain anomalously low value of the thermal-expansion coefficient.

In the most complicated manner the paraprocess appears in ferromagnetics (in ferrites also) with so called òÀÜweakòÀÝ magnetic sublattice. In these ferromagnetics not only ferromagnetic paraprocess exists, but anˆà antiferromagnetic paraprocess appears as well. These effects can be considered as a unidirectional exchange anisotropy appearance. This concept allow to explain various anomalous phenomena in ferrites with a òÀÜweakòÀÝ sublattice.

 

Physics of magnetic phenomena

36 hours, 9-th term

Part 3. Magnetic anisotropy, magnitostriction and domain structure of ferromagnets.

The magnetic properties, magnetic anisotropy, magnetostriction on the base of modern theoretical and experimental investigations of ferromagnetics and their alloys. One-ion, exchange and induced magnetic anisotropy. The connection with electron structure of 3d and 4d ions. The spin distribution on the basis of micromagnetism theory for domain structure and domain walls. Magnetic hysteresis in the models of dislocations, internal tensions, magnetization rotation. The peculiarities of magnetic properties for hard and soft magnetic materials.

 

The magnetic structures

36 hours, 7-th term

 

Condition for stability of different magnetic structures (ferromagnetic, antiferromagnetic, ferrimagnetic etc.) The fundamental properties of antiferromagnets and theˆà theory of noncollinear weakly ferromagnetic state. The ferrimagnetic state is anlyzed within the scope of the Neel model. The spin-reorintation transitions in different types of magnets. The properties of spin-glass state.

 

Magnetic nanostructures

and low-dimensional objects.

36 hours, 9-th term

 

Ultrathin films and multilayer structures, their classification. Hamiltonian and thermodynamic potential. Basic dynamical parameters.Quantum dimensional effects. Magnetization processes and phase diagrams. Galvanomagnetic properties. Optical properties of multilayer structures Domain structure. Method of mathematic modelling in magnetic nanostructure physics. Macroscopic quantum tunneling of magnetization (theory and experiment). Practical application of magnetic multilayer films and nanostructures.

 

Magnetic dielectrics and semiconductors

32 hours, 10-th term

 

The different types of ferrites, ferrimagnetic and specific semiconducting properties. The localized states of the conducting electrons due to the antiferromagnetic s-d exchange and the nature of anomalies of isotropic magnetoresistance of ferrites. The interpretation of the basic physical effects in ferrites. The anomalies of physical properties at Curie point and at magnetic compensationˆà point. The pecularities of the magnetic semiconductors: a giant red shift of the optical absorption edge; a giant maxima of the modulus of the negative magnetoresistance and the positive magnetoresistance inside the Curie point region; a low-temperature metal-isolator transition; photomagnetic effect; a paramagnetic Curie point increase due to impurities;a nonuniform magnetic states in degenerate semiconductors are explained by s-d(f) exchange and arising of the magnetic impurity states - ferrons. The possible phase transition spin glass - paramagnetism in semiconducting spin glasses.

 

Dynamic properties of magnetic substances

32 hours, 10-th term

 

Magnetic resonance concept. Cyclotron resonance. Electron spin resonance. Magnetoacoustic resonance. Muon spin resonance. Magnetically ordered substances at alternating magnetic fields. Ferro-, ferri- and antiferromagnetic resonances. Spin-wave resonance in ferromagnets. Dispersion law. Submillimeter spectroscopy of rare-earth weak ferromagnets.ˆà Magnetooptical phenomena in magnetically ordered substances.

 

Physics of rare earth metals and alloys

32 hours, 10-th term

 

The magnetic and electric properties and crystalline structures of rare earth metals and alloys on the base of modern theoretical and experimental approaches. The indirect exchange, magnetic phase transition, magneto-crystalline and magneto-elastic interactions, magneto- caloric effect, magnetic anisotropy and giant magnetostriction. Kinetic properties. The exchange interactions, crystalline and magnetic structures of rare earthˆà intermetallic compounds. The application of rare earth compounds.

 

Modern Magnetic Materials

32 hours, 10-th term

 

Modern physics of magnetic phenomena and magnetic materials. Basic types of magnetic materials and their applications.

Amorphous materials: methods of preparation and structure. Exchange interactions, random and induced magnetic anisotropy. Primary magnetic structures: speromagnetics, sperimagnetics, asperomagnetics, spin glasses. Common models describing magnetic state.

Rare earth amorphous magnets. Phase transitions. Competing exchange interactions. Role of random magnetic anisotropy. Dependence of basic magnetic parameters on concentration, invares. Peculiarities of magnetization processes.

Hydrides and nitrides of rare earth alloys and compounds.ˆà Influence of hydrogen and nitrogen on exchange interactions and magnetic anisotropy in amorphous alloys and crystalline compounds.

Nanocrystal magnets. Methods of preparation, magnetic peculiarities. Applications.

Fullerens. Methods of preparation. Embedding of magnetic atoms into fulleren structures. Aspects of development and applications of fullerens.

Nanotubes. Methods of preparation. Basic physical properties.

Fractal structures in magnets. Methods of preparation. Magnet peculiarities.

 

Single crystal growth and contemporary methods of the preparation of materials

32 hours, 10-th term

 

General aspects of the theory and practice of crystal growth, history and present state.

General thermodynamics notions, the Gibbse phases rule. State diagrams of one- two- and three- component systems, the principles of their construction and types of diagrams.

The mechanisms and kinetics of crystallization: phase equilibrium; kinetics of tangential and normal growth; dislocation mechanism of the growth; influence of admixtures on the growth process.

Fundamentals of present methods of the preparation of magnetic and ferroelectric materials: single crystal growth from solution; from flux; from melt; thin films preparation by method of lasers sputtering; preparation of nanocrystalline magnetic materials.

 

Phase transitions and renormalization group

32 hours, 8-th term

 

Critical phenomena in magnets and their description. Critical indices. Method of the molecular field and phenomenological Landau theory. Similarity hypothesis. Ginzburg-Landau Hamiltonian. Gaussian model. Renormalization groups. Gaussian fixed point. e-expansion. Applications of the renormalization group method to concrete models.