scholarly journals Electronic Heat Capacity and Lattice Softening of Partially Deuterated Compounds of κ-(BEDT-TTF)2Cu[N(CN)2]Br

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 2
Author(s):  
Yuki Matsumura ◽  
Shusaku Imajo ◽  
Satoshi Yamashita ◽  
Hiroki Akutsu ◽  
Yasuhiro Nakazawa
Keyword(s):  
Heat Capacity ◽  
Magnetic Fields ◽  
Volume Fraction ◽  
Heat Capacities ◽  
Organic Superconductors ◽  
Electronic Heat Capacity ◽  
Temperature Dependences ◽  
Electronic Heat ◽  
Capacity Data ◽  
Lattice Softening

Thermodynamic investigation by calorimetric measurements of the layered organic superconductors, κ-(BEDT-TTF)2Cu[N(CN)2]Br and its partially deuterated compounds of κ-(d[2,2]-BEDT-TTF)2Cu[N(CN)2]Br and κ-(d[3,3]-BEDT-TTF)2Cu[N(CN)2]Br, performed in a wide temperature range is reported. The latter two compounds were located near the metal–insulator boundary in the dimer-Mott phase diagram. From the comparison of the temperature dependences of their heat capacities, we indicated that lattice heat capacities of the partially deuterated compounds were larger than that of the pristine compound below about 40 K. This feature probably related to the lattice softening was discussed also by the sound velocity measurement, in which the dip-like structures of the Δv/v were observed. We also discussed the variation of the electronic heat capacity under magnetic fields. From the heat capacity data at magnetic fields up to 6 T, we evaluated that the normal-state γ value of the partially deuterated compound, κ-(d[3,3]-BEDT-TTF)2Cu[N(CN)2]Br, was about 3.1 mJ K−2 mol−1. Under the magnetic fields higher than 3.0 T, we observed that the magnetic-field insulating state was induced due to the instability of the mid-gap electronic state peculiar for the two-dimensional dimer-Mott system. Even though the volume fraction was much reduced, the heat capacity of κ-(d[3,3]-BEDT-TTF)2Cu[N(CN)2]Br showed a small hump structure probably related to the strong coupling feature of the superconductivity near the boundary.

Quadratic temperature dependence of electronic heat capacities in the κ-type organic superconductors

2016 ◽  
Vol 30 (13) ◽  
pp. 1642014 ◽  
Author(s):  
Shusaku Imajo ◽  
Satoshi Yamashita ◽  
Hiroki Akutsu ◽  
Yasuhiro Nakazawa
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
Heat Capacities ◽  
Organic Superconductors ◽  
Pairing Symmetry ◽  
Electronic Heat Capacity ◽  
Text Type ◽  
Electronic Heat ◽  
Normal States ◽  
Quadratic Temperature

We carried out a systematic measurement and data analysis of low-temperature heat capacities of three BEDT-TTF-based superconductive compounds with [Formula: see text]-type structure, where BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene so as to compare the character of the quasi-particle excitations reflected in the electronic heat capacity. We used an original relaxation calorimetry cell with much reduced addenda heat capacity as compared with previous works. The three compounds, [Formula: see text]-(BEDT-TTF)2Cu(NCS)2, [Formula: see text]-(BEDT-TTF)2Ag(CN)2H2O, [Formula: see text]-(BEDT-TTF)4Hg[Formula: see text]Br8 show distinct quadratic temperature dependence in their electronic heat capacity obtained by subtracting normal states data obtained by applying magnetic fields from the 0 T data. The line-nodal gap due to [Formula: see text]-wave pairing symmetry is suggested as common phenomena of the superconductivity of the [Formula: see text]-type compounds.

Rotational tunneling of methyl groups and the electronic heat capacity of EtMe3Sb[Pd(dmit)2]2 under magnetic fields

2016 ◽  
Vol 30 (13) ◽  
pp. 1642007
Author(s):  
Satoshi Yamashita ◽  
Masayuki Yoshizumi ◽  
Hiroki Akutsu ◽  
Yasuhiro Nakazawa
Keyword(s):  
Heat Capacity ◽  
Magnetic Fields ◽  
Spin Glasses ◽  
Methyl Groups ◽  
Spin Liquid ◽  
Electronic Heat Capacity ◽  
Capacity Measurement ◽  
Electronic Heat ◽  
Heat Capacity Measurements ◽  
The Stability

In order to discuss the stability of the gapless features in the spin liquid state against magnetic fields, we report results and analyses of low-temperature heat capacity measurements of EtMe3Sb[Pd(dmit)2]2 under magnetic fields. The large upturn of [Formula: see text] at 0 T observed previously in EtMe3Sb[Pd(dmit)2]2 can be attributed to the rotational tunneling of the methyl groups in the counter cations and this upturn is suppressed by applying magnetic fields. The phenomenological resemblance of the feature under magnetic field was confirmed by comparative discussion of heat capacity measurement of metal complex of [Cu(acac)(OCH[Formula: see text]]2 having similar methyl groups. The gapless character evidenced by the finite electronic heat capacity coefficient, [Formula: see text] was found to be retained upon applying 17 T in EtMe3Sb[Pd(dmit)2]2, which means that spin liquid ground state is stable against high magnetic fields. The finite [Formula: see text] in the spin liquid compounds is considered to be related to a kind of density of states in spin excitations rather than those determined by disorders such as spin glasses.

scholarly journals Теплоемкость и магнитокалорический эффект соединений LaFe-=SUB=-11.2-x-=/SUB=-Mn-=SUB=-x-=/SUB=-Co-=SUB=-0.7-=/SUB=-Si-=SUB=-1.1-=/SUB=- (x=0, 0.1, 0.2, 0.3)

2020 ◽  
Vol 62 (5) ◽  
pp. 752
Author(s):  
Н.З. Абдулкадирова ◽  
А.М. Алиев ◽  
А.Г. Гамзатов ◽  
P. Gebara
Keyword(s):  
Heat Capacity ◽  
Magnetic Fields ◽  
Curie Temperature ◽  
Specific Heat ◽  
Magnetocaloric Effect ◽  
Intermetallic Compounds ◽  
Indirect Method ◽  
Direct Method ◽  
Capacity Data ◽  
Value Changes

The specific heat and magnetocaloric effect of the LaFe11.2-хMnxCo0.7Si1.1 intermetallic compounds (x = 0.1, 0.2, 0.3) were measured in the temperature range 80–300 K and in magnetic fields up to 8 T. The magnetocaloric effect (MCE) was estimated using two methods: direct method in cyclic magnetic fields, as well as an indirect method from heat capacity data. It was shown that an increase in the concentration of Mn atoms leads to a shift in the Curie temperature of the TC toward lower temperatures, while the FM value changes slightly.

scholarly journals Schottky anomaly and Néel temperature treatment of possible perturbed hydrogenated AA-stacked graphene, SiC, and h-BN bilayers

RSC Advances ◽  
2019 ◽  
Vol 9 (71) ◽  
pp. 41569-41580 ◽  
Author(s):  
Bui D. Hoi ◽  
Le T. T. Phuong ◽  
Vo T. Lam ◽  
Doan Q. Khoa ◽  
Tran Tien ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Heat Capacity ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Temperature Treatment ◽  
Electronic Heat Capacity ◽  
Néel Temperature ◽  
Schottky Anomaly ◽  
Electronic Heat ◽  
Pauli Susceptibility

The potential of manipulating the electronic heat capacity and Pauli susceptibility of hydrogenated AA-stacked graphene, silicon carbide, and hexagonal boron nitride bilayers is studied.

Magnetic ordering and enhanced electronic heat capacity in insulatingL2RuO5(L=Pr,Nd, Sm, Gd, and Tb)

2001 ◽  
Vol 63 (14) ◽  
Author(s):  
G. Cao ◽  
S. McCall ◽  
Z. X. Zhou ◽  
C. S. Alexander ◽  
J. E. Crow ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Magnetic Ordering ◽  
Electronic Heat Capacity ◽  
Electronic Heat
Sign in / Sign up

Export Citation Format

Share Document