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, we have attempted through this course to steer a middle 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, 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 “weak”
magnetic sublattice. In these ferromagnetics not only ferromagnetic paraprocess
exists, but an 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 “weak” 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 the 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 compensation 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. 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 earth intermetallic compounds. The
application of rare earth compounds.
Modern
Magnetic Materials
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. 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.
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.