Heat capacity study of the doping effect of paramagnetic impurity in organic spin-Peierls system: p-CyDOV radical crystal

K. Mukai, M. Yanagimoto, S. Tanaka, M. Mito, Tatsuya Kawae, K. Takeda

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Heat capacity studies were performed for the doped verdazyl radical crystals, (p-CyDOV)1-x(p-CyDTV)x (x = 0, 0.01, and 0.07), to clarify the effect of magnetic impurity (p-CyDTV) on the spin-Peierls (SP) transition (TSP = 15.0 K) of 3-(4-cyanophenyl)-1,5-dimethyl-6-oxoverdazyl (p-CyDOV) radical crystal, where the > C=O group in p-CyDOV is replaced by the > C=S group in p-CyDTV. The antiferromagnetic (AFM) transitions were observed at TN = 0.135, 0.290, and 0.164 K for the crystals with x = 0, 0.01, and 0.07, respectively, indicating the coexistence of AFM order and SP state in the systems with x = 0 and 0.01, and the appearance of the single phase of AFM order in the system with x = 0.07 below TN = 0.164 K. However, the heat capacity anomaly associated with the SP transition was not found at TSP = 15.0 K for the pure p-CyDOV crystal (x = 0), whereas the anomalous broad peak in the heat capacity was observed at T′SP = 5.6 K. The entropy consumption in the above broad peak was about 3% of the total spin entropy R ln 2, suggesting that this transition may relate to SP transition. The pressure induced by the solidification of the Apiezon-N grease, which was used as the thermal binder for the heat capacity measurement, at low temperature may affect the shift of the SP transition temperature. The doping effects for the organic SP system (p-CyDOV), which include the temperature (T: TSP and TN - impurity (x) phase diagram, are similar to those for the inorganic SP system (CuGeO3), although the one-dimensionality, i.e., |zJ′/ J| ≅ 6 × 10-4, in the organic p-CyDOV system is much higher than that (∼10-1) in the inorganic CuGeO3 system, where zJ′ and J are inter- and intra-chain exchange interactions. This work is the first report of the heat capacity study of the doping effect on the organic SP transition system.

Original languageEnglish
Pages (from-to)2091-2098
Number of pages8
JournalPolyhedron
Volume22
Issue number14-17
DOIs
Publication statusPublished - Jul 15 2003

Fingerprint

Specific heat
Doping (additives)
specific heat
Impurities
impurities
Crystals
crystals
Entropy
Exchange interactions
Lubricating greases
Superconducting transition temperature
Phase diagrams
Binders
Solidification
entropy
greases
spin temperature
Temperature
solidification
transition temperature

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Heat capacity study of the doping effect of paramagnetic impurity in organic spin-Peierls system : p-CyDOV radical crystal. / Mukai, K.; Yanagimoto, M.; Tanaka, S.; Mito, M.; Kawae, Tatsuya; Takeda, K.

In: Polyhedron, Vol. 22, No. 14-17, 15.07.2003, p. 2091-2098.

Research output: Contribution to journalArticle

Mukai, K. ; Yanagimoto, M. ; Tanaka, S. ; Mito, M. ; Kawae, Tatsuya ; Takeda, K. / Heat capacity study of the doping effect of paramagnetic impurity in organic spin-Peierls system : p-CyDOV radical crystal. In: Polyhedron. 2003 ; Vol. 22, No. 14-17. pp. 2091-2098.
@article{6275307012a34dc6b02288e68f861f35,
title = "Heat capacity study of the doping effect of paramagnetic impurity in organic spin-Peierls system: p-CyDOV radical crystal",
abstract = "Heat capacity studies were performed for the doped verdazyl radical crystals, (p-CyDOV)1-x(p-CyDTV)x (x = 0, 0.01, and 0.07), to clarify the effect of magnetic impurity (p-CyDTV) on the spin-Peierls (SP) transition (TSP = 15.0 K) of 3-(4-cyanophenyl)-1,5-dimethyl-6-oxoverdazyl (p-CyDOV) radical crystal, where the > C=O group in p-CyDOV is replaced by the > C=S group in p-CyDTV. The antiferromagnetic (AFM) transitions were observed at TN = 0.135, 0.290, and 0.164 K for the crystals with x = 0, 0.01, and 0.07, respectively, indicating the coexistence of AFM order and SP state in the systems with x = 0 and 0.01, and the appearance of the single phase of AFM order in the system with x = 0.07 below TN = 0.164 K. However, the heat capacity anomaly associated with the SP transition was not found at TSP = 15.0 K for the pure p-CyDOV crystal (x = 0), whereas the anomalous broad peak in the heat capacity was observed at T′SP = 5.6 K. The entropy consumption in the above broad peak was about 3{\%} of the total spin entropy R ln 2, suggesting that this transition may relate to SP transition. The pressure induced by the solidification of the Apiezon-N grease, which was used as the thermal binder for the heat capacity measurement, at low temperature may affect the shift of the SP transition temperature. The doping effects for the organic SP system (p-CyDOV), which include the temperature (T: TSP and TN - impurity (x) phase diagram, are similar to those for the inorganic SP system (CuGeO3), although the one-dimensionality, i.e., |zJ′/ J| ≅ 6 × 10-4, in the organic p-CyDOV system is much higher than that (∼10-1) in the inorganic CuGeO3 system, where zJ′ and J are inter- and intra-chain exchange interactions. This work is the first report of the heat capacity study of the doping effect on the organic SP transition system.",
author = "K. Mukai and M. Yanagimoto and S. Tanaka and M. Mito and Tatsuya Kawae and K. Takeda",
year = "2003",
month = "7",
day = "15",
doi = "10.1016/S0277-5387(03)00244-4",
language = "English",
volume = "22",
pages = "2091--2098",
journal = "Polyhedron",
issn = "0277-5387",
publisher = "Elsevier Limited",
number = "14-17",

}

TY - JOUR

T1 - Heat capacity study of the doping effect of paramagnetic impurity in organic spin-Peierls system

T2 - p-CyDOV radical crystal

AU - Mukai, K.

AU - Yanagimoto, M.

AU - Tanaka, S.

AU - Mito, M.

AU - Kawae, Tatsuya

AU - Takeda, K.

PY - 2003/7/15

Y1 - 2003/7/15

N2 - Heat capacity studies were performed for the doped verdazyl radical crystals, (p-CyDOV)1-x(p-CyDTV)x (x = 0, 0.01, and 0.07), to clarify the effect of magnetic impurity (p-CyDTV) on the spin-Peierls (SP) transition (TSP = 15.0 K) of 3-(4-cyanophenyl)-1,5-dimethyl-6-oxoverdazyl (p-CyDOV) radical crystal, where the > C=O group in p-CyDOV is replaced by the > C=S group in p-CyDTV. The antiferromagnetic (AFM) transitions were observed at TN = 0.135, 0.290, and 0.164 K for the crystals with x = 0, 0.01, and 0.07, respectively, indicating the coexistence of AFM order and SP state in the systems with x = 0 and 0.01, and the appearance of the single phase of AFM order in the system with x = 0.07 below TN = 0.164 K. However, the heat capacity anomaly associated with the SP transition was not found at TSP = 15.0 K for the pure p-CyDOV crystal (x = 0), whereas the anomalous broad peak in the heat capacity was observed at T′SP = 5.6 K. The entropy consumption in the above broad peak was about 3% of the total spin entropy R ln 2, suggesting that this transition may relate to SP transition. The pressure induced by the solidification of the Apiezon-N grease, which was used as the thermal binder for the heat capacity measurement, at low temperature may affect the shift of the SP transition temperature. The doping effects for the organic SP system (p-CyDOV), which include the temperature (T: TSP and TN - impurity (x) phase diagram, are similar to those for the inorganic SP system (CuGeO3), although the one-dimensionality, i.e., |zJ′/ J| ≅ 6 × 10-4, in the organic p-CyDOV system is much higher than that (∼10-1) in the inorganic CuGeO3 system, where zJ′ and J are inter- and intra-chain exchange interactions. This work is the first report of the heat capacity study of the doping effect on the organic SP transition system.

AB - Heat capacity studies were performed for the doped verdazyl radical crystals, (p-CyDOV)1-x(p-CyDTV)x (x = 0, 0.01, and 0.07), to clarify the effect of magnetic impurity (p-CyDTV) on the spin-Peierls (SP) transition (TSP = 15.0 K) of 3-(4-cyanophenyl)-1,5-dimethyl-6-oxoverdazyl (p-CyDOV) radical crystal, where the > C=O group in p-CyDOV is replaced by the > C=S group in p-CyDTV. The antiferromagnetic (AFM) transitions were observed at TN = 0.135, 0.290, and 0.164 K for the crystals with x = 0, 0.01, and 0.07, respectively, indicating the coexistence of AFM order and SP state in the systems with x = 0 and 0.01, and the appearance of the single phase of AFM order in the system with x = 0.07 below TN = 0.164 K. However, the heat capacity anomaly associated with the SP transition was not found at TSP = 15.0 K for the pure p-CyDOV crystal (x = 0), whereas the anomalous broad peak in the heat capacity was observed at T′SP = 5.6 K. The entropy consumption in the above broad peak was about 3% of the total spin entropy R ln 2, suggesting that this transition may relate to SP transition. The pressure induced by the solidification of the Apiezon-N grease, which was used as the thermal binder for the heat capacity measurement, at low temperature may affect the shift of the SP transition temperature. The doping effects for the organic SP system (p-CyDOV), which include the temperature (T: TSP and TN - impurity (x) phase diagram, are similar to those for the inorganic SP system (CuGeO3), although the one-dimensionality, i.e., |zJ′/ J| ≅ 6 × 10-4, in the organic p-CyDOV system is much higher than that (∼10-1) in the inorganic CuGeO3 system, where zJ′ and J are inter- and intra-chain exchange interactions. This work is the first report of the heat capacity study of the doping effect on the organic SP transition system.

UR - http://www.scopus.com/inward/record.url?scp=0042806333&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0042806333&partnerID=8YFLogxK

U2 - 10.1016/S0277-5387(03)00244-4

DO - 10.1016/S0277-5387(03)00244-4

M3 - Article

AN - SCOPUS:0042806333

VL - 22

SP - 2091

EP - 2098

JO - Polyhedron

JF - Polyhedron

SN - 0277-5387

IS - 14-17

ER -