Contact persons

Assoc. prof. Alžbeta Orendáčová, DrSc
Email: alzbeta.orendacova@upjs.sk
Phone: +421 (055) 234 2280

Prof. Alexander Feher, DrSc
Email: alexander.feher@upjs.sk
Phone: +421 (055) 234 2219, 2220

Address: Park Angelinum 9, 04154 Košice

Experimental facilities

Laboratory of quantum magnetism is a collective name for a group of three separate laboratories.
Laboratory of low-temperature physics I is equipped with Sartorius analytic scales with the precision of 0.1 mg, a precise cutting machine with a diamond wire and a cryostat with 1 K pot working at temperatures from 1.2 K to 10 K and magnetic fields up to 3 T. In the cryostat, a steady-state method of thermal conductivity and a heat-pulse method of specific heat are implemented.
Laboratory of low-temperature physics II is equipped with a TTL 200 Oxford Instruments 3He-4He dilution refrigerator operating without liquid nitrogen. The experiments of specific heat, thermal conductivity, magnetocaloric effect, and ac susceptibility can be performed at temperatures from 50 mK to 3 K and in the magnetic field up to 9 T.
Laboratory of low-temperature physics – minirefrigerator is equipped with a 3He-4He dilution minirefrigerator MINIDIL, made by Air Liquid and operating without liquid nitrogen at temperatures from 35 mK to 2.5 K and in magnetic field up to 7 T. The experiments of specific heat and ac permitivity can be performed.

Research

A basic conventional characteristics of the studied magnetic system, so-called magneto-structural correlations and phase transitions are investigated using specific heat measurements based on the „dual-slope“ relaxation method in the temperature region from 40 mK to 4 K and in magnetic field from 0 to 9 T. The sample size/mass is in the range from 1mm/10mg to 1 cm/200 mg. In addition to single crystals, also powder samples or polycrystalline compounds can be studied in the form of pressed pellets. The information about the sensitivity of the sample to the chemical composition of the fixing material (glue, varnish, grease) is required before mounting the sample.
Structural changes and phase transitions can be indicated by the study of dielectric properties using the ac permitivity in the frequency range from 50 Hz to 20 kHz at temperatures from 35 mK to 2.5 K and magnetic field up to 7 T.
The heat transport is studied by a steady-state method in zero magnetic field at temperatures from 100 mK to 4 K. The samples are in the shape of a needle with the length from 5mm to 5 cm. The information about the sensitivity of the sample to the chemical composition of the fixing material (glue, varnish, grease) is required before mounting of the sample.
Magneto-caloric effect can be investigated using quasi-adiabatic magnetization at temperatures from 100 mK to 4 K and field to 9 T. Sample size/mass can be about 1 cm/500 mg, depending on the density of magnetic centers. Besides single crystals, powder samples or polycrystalline compounds can be studied in the form of pressed pellets. The information about the sensitivity of the sample to the chemical composition of the fixing material (glue, varnish, grease) is required before mounting the sample.
Spin dynamics and magnetic relaxation can be studied by the ac susceptibility in zero magnetic field using a home made ac susceptometer based on a standard mutual inductance method operating at temperatures from 100 mK to 4 K and frequencies from 1 Hz to 1 kHz. Sample size/mass can be about 1 cm/500 mg. Besides single crystals, powder samples or polycrystalline compounds can be studied in the form of pressed pellets. The information about the sensitivity of the sample to the chemical composition of the fixing material (glue, varnish, grease) is required before mounting of the sample.

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