JOPSS - Search Results

Journal Articles

Giant multiple caloric effects in charge transition ferrimagnet

Kosugi, Yoshihisa*; Goto, Matato*; Tan, Z.*; Kan, Daisuke*; Isobe, Masahiko*; Yoshii, Kenji; Mizumaki, Masaichiro*; Fujita, Asaya*; Takagi, Hidenori*; Shimakawa, Yuichi*

Scientific Reports (Internet), 11(1), p.12682_1 - 12682_8, 2021/06

https://doi.org/10.1038/s41598-021-91888-8

Times Cited Count：5 Percentile：43.44(Multidisciplinary Sciences)

Caloric effects of solids provide more efficient and environment-friendly innovative refrigeration systems compared to the widely-used conventional vapor compressive cooling systems. Exploring novel caloric materials is challenging but critically important in developing future technologies. Here we discovered that the quadruple perovskite structure ferrimagnet BiCu $_{3}$ Cr $_{4}$ O $_{12}$ shows a large multicaloric effect at the first-order charge transition occurred around 190 K. Large latent heat and the corresponding isothermal entropy changes 28.2 J K $^{-1}$ kg $^{-1}$ can be fully utilized by applying both magnetic fields (magnetocaloric effect) and pressure (barocaloric effect). Adiabatic temperature changes reach 3.9 K for the 50 kOe magnetic field and 4.8 K for the 4.9 kbar pressure, and thus highly efficient thermal controls are achieved by multiple ways.

Journal Articles

Local structural analysis of half-metallic ferromagnet CrO

Kodama, Katsuaki; Ikeda, Kazutaka*; Isobe, Masahiko*; Takeda, Hikaru*; Ito, Masayuki*; Ueda, Yutaka*; Shamoto, Shinichi; Otomo, Toshiya*

Journal of the Physical Society of Japan, 85(9), p.094709_1 - 094709_5, 2016/09

https://doi.org/10.7566/JPSJ.85.094709

Times Cited Count：1 Percentile：11.35(Physics, Multidisciplinary)

Journal Articles

Devil's flower resulting from a successive charge disproportionation of NaV $_{2}$ O $_{5}$ ; Understanding of the details of the Ising spin and the competitive interactions which made the devil's flower bloom

Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi*; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.

Hoshako, 21(2), p.87 - 96, 2008/03

http://ci.nii.ac.jp/naid/10020476047

Devil's flower has been found in a temperature-pressure phase diagram of NaV $_{2}$ O $_{5}$ , which shows a charge disproportionation (CD) at ambient pressure. By a complementary use of an X-ray structural analysis and a resonant X-ray diffraction, which is sensitive to CD, we have investigated the structural relationship between two ground states appeared in lower and higher pressure regions including the charge arrangements. It has been clarified that two equivalent types of charge arrangement in CD correspond to the Ising variable in NaV $_{2}$ O $_{5}$ . The atomic shifts are regarded as linearly coupled to the Ising spins. The results lead us to the conclusion that it is the first time that the devil's flower blooms in a charge-disproportionation system. The results also lead us to a hypothesis that the competitive interactions between a Ising spins may result from the Ising spin-phonon coupling.

Journal Articles

Structural relations between two ground states of NaV $_{2}$ O $_{5}$ under high pressure; A Synchrotron X-ray diffraction study

Owada, Kenji; Fujii, Yasuhiko; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi; Noda, Yukio*; Osumi, Hiroyuki*; Ikeda, Naoshi*; Shobu, Takahisa; Isobe, Masahiko*; et al.

Physical Review B, 76(9), p.094113_1 - 094113_10, 2007/09

https://doi.org/10.1103/PhysRevB.76.094113

Times Cited Count：10 Percentile：44.46(Materials Science, Multidisciplinary)

Structural relations between two ground states of the ANNNI (Axial Next Nearest Neighbor Ising) compound NaV $_{2}$ O $_{5}$ , C $_{1/4}$ - and C $_{0}$ -phases below and above the transition pressure $P_{rm C}$ = 1 GPa, were investigated by X-ray diffraction and scattering techniques. The structure of the C $_{0}$ -phase is well explained by the () pattern which is one of four layers () of the C $_{1/4}$ -phase, however, the amount of the atomic shifts under the conditions 1.6 GPa and 6 K is 27% that under ambient pressure. On the other hand, resonant X-ray scattering showed that the charges are disproportionated under high pressure. Based on these facts, it was concluded that charge disproportionation corresponds to the Ising variable in NaV $_{2}$ O $_{5}$ , where the atomic shifts are regarded as linearly coupled to the Ising spins. These results lead to the hypothesis that the competitive interactions between the Ising spins may result from the Ising spin-phonon coupling.

Journal Articles

Discovery of the "Devil's flower" in a charge-ordering system; Synchrotron X-ray diffraction study of NaV $_{2}$ O $_{5}$

Owada, Kenji; Fujii, Yasuhiko; Nakao, Hironori*; Murakami, Yoichi*; Isobe, Masahiko*; Ueda, Yutaka*

Modern Physics Letters B, 20(5), p.199 - 214, 2006/02

https://doi.org/10.1142/S0217984906010548

Times Cited Count：5 Percentile：21.81(Physics, Applied)

We review recent synchrotron diffraction studies of NaV $_{2}$ O $_{5}$ . The resonant X-ray scattering performed on a monoclinically-split single domain of NaV $_{2}$ O $_{5}$ shows a critically enhanced contrast between V $^{4+}$ and V $^{5+}$ ions. The results has led us to the unequivocal conclusion of the charge-order pattern of low-temperature phase of NaV $_{2}$ O $_{5}$ below $T_{rm c}$ = 35 K. In spite of the possible four types of configuration of the zig-zag-type charge-order patterns in the -plane (A, A', B and B'), the stacking sequence along the -axis is determined as the AAA'A' type by comparison with model calculations. By assigning the A and A' configurations to Ising spins and , one can reasonably explain the previously discovered "devil's staircase"-type behavior with respect to the modulation of layer-stacking sequences at high pressures and low temperatures, which clearly resembles the global phase diagram theoretically predicted by the ANNNI model, called "devil's flower". This is the first case that the devil's flower appears in such a charge-ordering system, where charge-order patterns are regarded as Ising spins.

Journal Articles

Charge-order pattern of the low-temperature phase from a monoclinic single domain of NaV $_{2}$ O $_{5}$ uniquely determined by resonant X-ray scattering

Owada, Kenji; Fujii, Yasuhiko; Katsuki, Yuya*; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi; Sawa, Hiroshi*; Ninomiya, Emi*; Isobe, Masahiko*; Ueda, Yutaka*

Physical Review Letters, 94(10), p.106401_1 - 106401_4, 2005/03

https://doi.org/10.1103/PhysRevLett.94.106401

Times Cited Count：24 Percentile：72.12(Physics, Multidisciplinary)

The present resonant X-ray scattering has been performed on a monoclinically-split single domain of NaV $_{2}$ O $_{5}$ . The observation of a critically enhanced contrast between V $^{4+}$ and V $^{5+}$ ions has led us to the unequivocal conclusion of the charge-order pattern of low-temperature phase of NaV $_{2}$ O $_{5}$ below $T_{rm c}$ = 35 K. In spite of the possible four types of configuration of the zig-zag-type charge-order patterns in the -plane (A, A', B and B'), the stacking sequence along the -axis is determined as the AAA'A' type by comparison with model calculations. By assigning the A and A' configurations to Ising spins, one can reasonably explain the previously discovered "devil's staircase"-type behavior with respect to the modulation of layer-stacking sequences at high pressures and low temperatures, which clearly resembles the global phase diagram theoretically predicted by the ANNNI model.

Oral presentation

Local structural analysis on half metallic ferromagnet CrO

Kodama, Katsuaki; Ikeda, Kazutaka*; Takeda, Hikaru*; Isobe, Masahiko*; Ito, Masayuki*; Ueda, Yutaka*; Shamoto, Shinichi; Otomo, Toshiya*

no journal, ,

no abstracts in English

Oral presentation

Local structural analysis on half metallic ferromagnet CrO by atomic pair distribution function

Kodama, Katsuaki; Shamoto, Shinichi; Ikeda, Kazutaka*; Otomo, Toshiya*; Takeda, Hikaru*; Isobe, Masahiko*; Ito, Masayuki*; Ueda, Yutaka*

no journal, ,

no abstracts in English

Oral presentation

Local structural analysis on half metallic ferromagnet CrO

Kodama, Katsuaki; Ikeda, Kazutaka*; Takeda, Hikaru*; Isobe, Masahiko*; Ito, Masayuki*; Ueda, Yutaka*; Shamoto, Shinichi; Otomo, Toshiya*

no journal, ,

no abstracts in English

Presentation/Publication Type

Journal/Book Title

Meeting title

First Author

Keyword

Language

Publication Year

Held year of conference

Giant multiple caloric effects in charge transition ferrimagnet

Local structural analysis of half-metallic ferromagnet CrO

Devil's flower resulting from a successive charge disproportionation of NaV $_{2}$ O $_{5}$ ; Understanding of the details of the Ising spin and the competitive interactions which made the devil's flower bloom

Structural relations between two ground states of NaV $_{2}$ O $_{5}$ under high pressure; A Synchrotron X-ray diffraction study

Discovery of the "Devil's flower" in a charge-ordering system; Synchrotron X-ray diffraction study of NaV $_{2}$ O $_{5}$

Charge-order pattern of the low-temperature phase from a monoclinic single domain of NaV $_{2}$ O $_{5}$ uniquely determined by resonant X-ray scattering

Local structural analysis on half metallic ferromagnet CrO

Local structural analysis on half metallic ferromagnet CrO by atomic pair distribution function

Local structural analysis on half metallic ferromagnet CrO