Combined effect of 2D nature and structural glass behaviour and true magnetic contribution to the low-temperature heat capacity of layered double hydroxides

abstract

Heat capacity of cobalt-aluminium and magnesium-aluminium layered double hydroxides (LDH) with the divalent-to-trivalent cations ratio (n) of 2 and 3, and intercalated with NO3-, CO32- and OH-, was measured as a function of temperature between 2 and 100 K. Magnetic contribution to the heat capacity (C-mag) of ConAl LDH was extracted from comparison of the C(T) dependences with the respective reduced dependences of their non-magnetic counterparts, MgnAl LDH. At the lowest measured temperatures, the magnetic contribution to the heat capacity (C-mag) of Co-containing LDH was found to be almost two orders of magnitude bigger than their lattice contribution. In a zero magnetic field, the low-temperature C-mag of Co2Al LDH was measured to be proportional to T-2.6, while for Co3Al LDH, C-mag similar to T-2 was observed. An application of an external magnetic field was revealed to converge these dependences to C-mag similar to T-3 in compounds with both n = 2 and 3. However, the conversion in Co2Al LDH occurred at lower values of external magnetic field (50 kOe) than that in Co3Al LDH (90 kOe).

keywords

MODE-DYNAMICS MODEL; THERMAL-CONDUCTIVITY; BOSON-PEAK; AL; INTERCALATION; ORDER

subject category

Chemistry; Materials Science; Mineralogy

authors

Tkác, V; Pashkevich, YG; Fertman, EL; Tarasenko, R; Cizmár, E; Feher, A; Fedorchenko, AV; Neves, CS; Vieira, DEL; Salak, AN

Groups

G2 - Photonic, Electronic and Magnetic Materials
G3 - Electrochemical Materials, Interfaces and Coatings

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

The authors thank A. Krivchikov for the fruitful and constructive discussion of the obtained results on the boson peak nature. This work was supported by the EU H2020 project European Microkelvin Platform (EMP) , grant agreement No. 824109. A.N. Salak and C.S. Neves acknowledge the financial support of national funds (OE) through FCT-Portugal in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Yu.G. Pashkevich acknowledges the financial support of the Swiss National Science Foundation through the individual grants IZSEZ0_212006 and IZSEZ0_215824 of the '' Scholars at Risk '' Program. The research done in the University of Aveiro was supported by the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC) . The research at the P.J. Safarik University was supported by the Slovak Research and Development Agency under grant Nos. APVV-22-0172, APVV-23-0006 and APVV-SK-PT-18-0019 and by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic under grant No. 1/0132/22.