arXiv subjects

A. Jedrzejczak

Publications and source records attributed to A. Jedrzejczak.

3 recordsLinked to original sources

arXiv2013

Anomalous ferromagnetism and non-Fermi-liquid behavior in the Kondo lattice CeRuSi2

The structural, electronic and magnetic properties of the Kondo-lattice system CeRuSi2 are experimentally investigated and analyzed in the series of other ternary cerium compounds. This system is shown to be an excellent model system demonstrating coexistence of the Kondo effect and anomalous ferromagnetism with a small magnetic moment which is confirmed by magnetic and μSR measurements. Data on specific heat, resistivity and Seebeck coefficient are presented. Being deduced from the resistivity and specific heat data, the non-Fermi-liquid behavior is observed at low temperatures, which is unusual for a ferromagnetic Kondo system. A comparison with other magnetic Kondo lattices is performed.

cond-mat.str-el↗

arXiv2005

Magnetic contribution to the specific heat of Pb_{1-x}Eu_{x}Te

The temperature dependence of the magnetic specific heat has been studied experimentally and theoretically in the semimagnetic semiconductor Pb_{1-x}Eu_{x}Te for x=0.027 and x=0.073, over the temperature range from 0.5 K to 10 K, in magnetic fields up to 2 T. There was a maximum in the magnetic specific heat between 1 and 3 K even in zero and low magnetic fields; this maximum shifted toward higher temperatures with increasing magnetic field. The experimental data have been analyzed in the framework of a model in which we assume that the ground states of europium ions are split even without an external magnetic field. We present arguments which support this assumption and we show that it is possible to find a physical mechanism leading to the splitting which can explain the experimental results.

cond-mat.other↗

arXiv2004

Thermoelectric studies of electronic properties of ferromagnetic GaMnAs layers

Thermoelectric power, electrical conductivity, and high field Hall effect were studied over a broad temperature range in ferromagnetic Ga(1-x)Mn(x)As epitaxial layers (0.015 70 K) the thermoelectric power in GaMnAs linearly increases with increasing temperature. That indicates the presence of a degenerate hole gas with the Fermi energy EF=220+-25 meV, nearly independent of Mn content (for 0.02<x<0.05). At lower temperatures GaMnAs layers with metallic-type conductivity show an additional contribution to the thermoelectric power with the maximum close to the Curie temperature. The layers exhibiting insulating electrical properties show 1/T-type increase of thermoelectric power at low temperatures.

cond-mat.mtrl-sci↗