Fyzikální ústav Akademie věd ČR

Research subjects at department 24

Magnetic nanomaterials

Nanomaterials based on magnetic oxides have formed an important part of our research almost for ten years. Major efforts have been directed towards finding novel methods for the synthesis of magnetic nanoparticles with precisely controlled magnetic properties and for advanced modification of their surface, including organic functionalization. At the same time, their magnetism and structural peculiarities have been thoroughly studied and compared to bulk samples based on SQUID magnetometry, x-ray and neutron diffraction measurements, Mössbauer spectroscopy, electron microscopy, and determination of oxygen stoichiometry. Principal studies have been focussed on monodisperse ferrite nanoparticles and nanocrystalline phases of ferromagnetic manganites La1-xSrxMnO3.

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Magnetocaloric effects in intermetallic compounds with first order transitions

In the field of magnetocaloric materials we follow a most recent trend where, due to their remarkable properties, Ni2MnX (X = Ga, In, Sn) based Heusler alloys are often considered as promising prototypical materials for magnetic refrigeration

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Dynamical mean-field theory for strongly correlated materials

We develop and apply the novel computational scheme LDA+DMFT to study materials with correlated electrons from first principles. LDA+DMFT is based on a combination of conventional band-structure methods, e.g., the local density approximation (LDA), with the dynamical mean-field theory (DMFT) for correlated electron systems. This allows us to capture quantum-mechanical and thermal spin, charge and orbital fluctuations and describe correlation driven metal-insulator transitions or formation of various types of long-range order, e.g.  The full text >>

Magnetic polarons in cobaltites

The cobaltites derived from LaCoO3 are prospective materials for their electronic and catalytic properties and represent also fundamental interest because of the temperature and pressure driven transitions between Co(III) ionic states of different spin numbers. The aim of the project is to investigate novel phenomenon where itinerant charge carriers convert the surrounding diamagnetic Co(III) states into magnetic ones, forming large spin polarons.  The full text >>

Thermoelectric cobaltites

The project deals with a fundamental research on novel oxide thermoelectric materials of p-type considered for the electric power generation using waste heat. As concerns the conversion efficiency of such thermoelectric generators, the materials should operate in wide temperature range and keep at the same time a high figure of merit, ZT =(S2R)T, where S is the Seebeck coefficient, R is the ratio of electric resistivity and thermal conductivity and T is the actual temperature of the thermoelectric segment.  The full text >>

ZnO-based magnetic semiconductors

The semiconductors based on ZnO doped by magnetic impurities belong to a new class of advanced materials, dilute magnetic semiconductors, which have recently received much experimental and theoretical attention as a suitable spin source for spintronic applications. Some of the highly doped wide band gap materials like (Zn,Mn)O reveal a ferromagnetic like behavior near and above room temperature, which is considered as a major criterium for spintronic applications.  The full text >>

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