Russian Physics Journal, Vol. 61, No. 2, June, 2018 (Russian Original No. 2, February, 2018)
HEAT CAPACITY OF V
-SOLID SOLUTIONS AT HELIUM
TEMPERATURES AND THEIR EVOLUTION DURING THERMAL
Vad. I. Surikov, Val. I. Surikov, S. V. Danilov, UDC (536.631+538.91):669-179
N. A. Semenyuk, V. A. Egorova, and N. G. Eysmont
The results of investigations of heat capacity С
of a series of V
-solid solutions at the temperatures
from 4.2 to 25 K are reported. It is found out that at these temperatures considerable contributions into the
heat capacity come from the crystal lattice proper and crystal lattice defects formed in the course of material
synthesis. The results of investigating the evolution of these materials during thermal cycling are also reported.
Keywords: heat capacity, solid solutions, thermal cycling, crystal lattice, crystal lattice defects.
In an earlier study we reported the results of investigations of low-temperature heat capacity of a series of
vanadium dioxide specimens within the homogeneity range [1, 2]. It was shown that at low temperatures a considerable
contribution into the heat capacity of an unalloyed specimen comes from readily excitable defects. In this work we
present the results of investigations of heat capacity С
of a series of V
-solid solutions at the temperatures from
4.2 to 25 K and the evolution of these materials during thermal cycling.
The specimens for investigations were prepared by the method of solid-state sintering of the required amount of
at the respective temperature regimes in evacuated quartz vessels. Heat treatment of the
compacted sample weights was performed in quartz tubes in three stages at the temperatures 900, 1000 and 1400 K .
All materials prepared for investigations represented fine-sized polycrystalline black-color powders.
Grading and verification of the specimens was performed by the X-ray diffraction methods in a Shimadzu
XRD-7000 diffractometer. The X-ray phase analysis demonstrated that the resulting preparations were single-phase
The electrical resistance in the vicinity of a metal – semiconductor phase transition was investigated on
compacted tablets by a standard four-point method with a relative measurement error no more than 5%.
The heat capacity was determined with an error up to 1% using a certified automated adiabatic Strelkov-type
calorimeter in a laboratory of the UrD RAS, which was manufactured at the Khabarovsk branch of the All-Russian
scientific-research institute of physicotechnical and radiotechnical measurements.
The results of heat capacity measurements for the specimens under study are presented in Fig. 1 in the
. It is evident from Fig. 1 that the temperature dependences of heat capacity are
monotonic, which seems to indicate the absence of any phase transitions in the investigated temperature interval.
Moreover the heat capacities of the compounds in question are quite different at the respective experimental
Omsk State Technical University, Omsk, Russia, e-mail: email@example.com; firstname.lastname@example.org;
email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org. Translated from Izvestiya
Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 30–33, February, 2018. Original article submitted April 6, 2017;
revision submitted October 11, 2017.
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