Novikov, V. V. and Bud'ko, S. L. and Matovnikov, A. and Mitroshenkov, N. and Pilipenko, K. S. and Konoplin, N. A. and Plokhikh, I. and Pfitzner, A. and Shevelkov, A. (2020) The specific features of phononic and magnetic subsystems of type-VII clathrate EuNi2P4. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 22 (32). pp. 18025-18034. ISSN 1463-9076, 1463-9084
Full text not available from this repository. (Request a copy)Abstract
A type-VII clathrate with a Eu(2+)guest embedded into a Ni-P covalent framework, EuNi2P4, was synthesized by a standard two-stage ampoule synthesis and confirmed to crystallize in the orthorhombic space groupFdddwith unit cell parametersa= 5.1829(1) angstrom,b= 9.4765(1) angstrom, andc= 18.9900(1) angstrom. A general technique for studying the lattice and magnetic properties of REE containing compounds is proposed. The temperature and field dependences of electrical resistivity rho(T,H), magnetizationM(T,H), magnetic susceptibility chi(T,H), heat capacityC(p)(T), and unit cell parametersa(T),b(T),c(T), and volumeV(T) were experimentally studied and analyzed at different pressures in the temperature range of 2-300 K. A cascade of anomalies in the studied dependences was identified and attributed to the magnetic phase transformation and peculiar lattice contributions at temperatures below 20 K. As a result of comparison with an isostructural clathrate SrNi2P4, the parameters of the magnetic and lattice contributions were determined. It is characteristic that the phase transition from the paramagnetic to the magnetically ordered state is not reflected in the temperature changes of the lattice parameters due to weak bonds between guest europium atoms and the Ni-P host matrix. We have constructed a tentativeH-Tphase diagram based on theM(T) andM(H) data, which includes 6 different phases. It is established that the anomalous lattice contribution to the clathrate heat capacityC(TLS)(T) appears due to the effect of two-level systems (TLS) in the Eu(2+)subsystem on the thermodynamic properties of EuNi2P4. The values of TLS parameters as well as the parameters of the magnetic subsystem of the clathrate were determined.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TEMPERATURE HEAT-CAPACITY; THERMAL-EXPANSION COEFFICIENT; MEAN-SQUARE DISPLACEMENTS; DEPENDENCE; PRESSURE; ATOMS; GLASS; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie Chemistry and Pharmacy > Institut für Anorganische Chemie > Chair Prof. Dr. Arno Pfitzner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 16 Mar 2021 07:18 |
| Last Modified: | 16 Mar 2021 07:18 |
| URI: | https://pred.uni-regensburg.de/id/eprint/43977 |
Actions (login required)
 |
View Item |
