Division of Physics of Magnetism

Main subject of research:

• Mechanisms of magnetocrystalline anisotropy and magnetoelastic interactions in amorphous and crystalline magnetic materials
• Magnetic and transport properties of high-T_C superconductors
• Domain structure and phase-transitions
• Influence of disorder on magnetic properties
• Coupling mechanism and finite - size effects in metallic and oxide heterostructures
• Metallic thin films, spin valves and multilayers for magnetoelectronics (GMR)
• Piezomagnetic properties of metallic glasses
• Surface and tunelling effects
• Technology of ceramic and single crystal growth of magnetic and high-Tc superconductors
• Structural phase transitions of cooperative Jahn - Teller type
• Photochromism and influence of light on transport and optical properties photoactive materials
• Properties of systems for spintronic applications: half and full Heusler alloys (thin films), half metallic oxides, e.g.: manganites (thin film and bulk), A₂Fe(Mo, Re)O₆ double perovskites (bulk), transition metal doped oxides (thin film of (La_0.5Sr_0.5)TiO₃:Co)
• Properties of nanocomposite materials: nanocrystalline soft magnets, metallic granular systems
• Ferromagnet/antiferromagnet interface and exchange interaction
• Selected aspects of biomagnetism, biotechnology and medical applications.

 
Materials studied:

• Single crystals of magnetic and magnetoelastic materials
• Ceramic and single crystal (bulk and thin film) of high-T_C superconductors
• Single crystal substrates for high-T_C superconducting thin films
• Magnetic/ non-magnetic and magnetic/ superconducting superlattices (heterostructures).
• Magnetic thin films and multilayers (with transition metals and rare earth elements)
• Amorphous and nanocrystalline materials (thin films and ribbons)
• Ferrofluids, and surface modified nanoparticles
• Molecular magnets
• Magnetic metalo-organic and supramolecular complexes
• Magnetic entities in the tissues of living organisms
• Sillenites, double tungstates, cobaltites and manganites.

 
Major experimental and technological facilities:

SQUID magnetometer MPMS-5 (Quantum Design)

• Temperature range - 2 - 360 K , magnetic field range - up to 5.5 T
• Possibility of measurements of two components of magnetic moment:
  - longitudinal (along the magnetic field direction)
  - transverse (perpendicular to the magnetic field direction, with possibility of estimation of magnetic anisotropy in the plane perpendicular to H).
• The sample holder with the Option of Horizontal Rotator. It allows to determine an anisotropy in a plane including the field direction.
• The optional holder for measurements under illumination.

Physical Property Measurement System (PPMS) Quantum Design
The system enables measurements of basic physical properties in the temperature range 2 - 350 K in magnetic fields up to 9 T for various orientations of the magnetic field. The system is equipped with the following options for:

• dc and ac magnetization measurements,
• transport measurements,
• torque measurements (in high magnetic fields sensitivity higher than sensitivity of SQUID),
• heat capacity measurements

Vibrating sample magnetometer (Oxford Instruments Ltd)

• temperature range: 4 - 1000 K at high accuracy of temperature measurements (additional low and high temperature calibration probes for reducing the ΔT offset)
• field range: ±1.1 T (electromagnet system with the de-gaussing procedures)
• angular excursion in horizontal plane: continuous 720 (±360) deg
• pick-up coils for normal and orthogonal components of magnetization
• equipped with additional probe for the magnetoresistivity measurements

  AC- susceptometer (Oxford Instruments Ltd)

  • field range: 0 - 30 mT
  • frequency range: 10 - 10.000 Hz
  • temperature range: 4 - 300 K

  Vibrating sample magnetometer (Princeton Applied Research model 4500)

  • temperature range: 2.0 - 250 K field range: 1.7 T angular excursion in horizontal plane: continuous 370 deg
  • equipped with additional high-pressure miniature container of a piston - cylinder type which enables measurements of magnetization under hydrostatic pressure up to 1.2 GPa.

  Three broadband spin echo spectrometers: fully automated, highly sensitive, designed to study nanometric magnetic materials

  • Frequency range of operation

    30-320 MHz
    300-1000 MHz
    20-600 MHz ( under construction)

  • Temperature of operation : 4.2 K, 77 K, RT
  • Advanced, self written software for NMR data analysis.

  EPR spectrometer at the X band and temperature range from 4.2 K to R.T.

  FMR spectrometer with strain modulated system (SMFMR)

  Setup for observation of magnetic domain structure (using Farady effect for transparent samples, and using Kerr effect for nontransparent samples, measurements can be performed over temperature range from 1.8 K to 700 K in different configuration of external magnetic field up to 5 T)

  Three terminal capacitance technique for magnetostriction and thermal expansion measurements

  • Temperature range 4-250 K,
  • Magnetic field range ± 12 T
  • Estimated sensitivity 0,5*10^-10 m;
  • Instrument includes AH2550A Ultra-Precession 1kHz Capacitance Bridge, which allows measuring changes in capacitance as small as 0.5 attofarad.

  Instrumentation to optical investigations (absorption, luminescence, Raman scattering, thermoabsorption, thermoluminescence) in broad spectral and temperature range (7μm - 0.2&\mu;m, 1.1K - 500K); cryogenics bases on CF1104 3.5K-500K and two home made cryostats 1.1K - 4.2K; excitation : high intensity Xenon short Arc lamp and lasers.

  Instrumentation to optical absorption and luminescence investigations in uniaxial stress up to 1000 Atm (1.5-4.2K)

  Instrumentation to optical absorption investigations in magnetic field for Voigt and Faraday configuration (superconducting magnet up to 9T with optical contr-cryostat 10-300K)

  Instrumentation to electron transport investigations (photoconductivity, TSC-thermostimulated current, photo-Hall (up to 0.7T)); cryogenics bases on two stage Closed Cycle Cryogenic refrigerator (10K-300K)

  Specialized instrumentation to investigations of photoactive materials (dark camera with open photomultiplier)

  X-ray powder diffraction and single crystal orientation

 
Technological facilities:

• Facilities for high pressure sputtering and MBE (Riber).
• Crystal growth of oxide materials by the Czochralski and floating zone method
• Cutting and polishing of oriented substrates and samples for optical investigation
• Solid state synthesis at high temperatures