SKM 2023 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 58: Poster: Superconductivity II
TT 58.24: Poster
Donnerstag, 30. März 2023, 15:00–18:00, P2/OG3
Study of the magnetocalotic effect in [Ni(C4H3O4)2(H2O)4] - A Potential Realization of a Spin-1 Spatially Anisotropic Square Lattice with Ferromagnetic Interactions — •Petro Danylchenko, Róbert Tarasenko, Erik Čižmár, Vladimír Tkáč, Alžbeta Orendáčová, and Martin Orendáč — Institute of Physics, Faculty of Science, Pavol Jozef Šafárik University, Park Angelinum 9, 04154 Košice, Slovakia
The magnetocaloric effect in [Ni(C4H3O4)2(H2O)4] was investigated using specific heat and magnetization measurements in the temperature range from 0.4 K to 50 K in magnetic fields up to 7 T. A magnetic entropy change -11.2 JK−1kg−1 at a temperature of about 3.5 K is achieved for magnetic field of 7 T. The temperature dependence of the magnetic specific heat in a zero magnetic field was compared with an S = 1 model with single-ion anisotropy parameters D and E (axial and rhombic). The best agreement was found for the parameters D/kB = 7.82 K and E/kB = 2.15 K. The divergence which appears between experimental and theoretical data at non-zero magnetic fields indicates the presence of additional factors in the system such as exchange interaction between magnetic ions. Broken-symmetry DFT calculations provided the values of ferromagnetic exchange interactions, J1/kB = 1.50 K and J2/kB = 1.44 K. The presence of such ferromagnetic correlations may explain the enhanced magnetocaloric effect. Supported by project No. APVV-18-0197.