Evidence of Charge Stripes, Charge-Spin-Orbital Coupling and Phase Transition in a Simple Copper Oxide CuO

鄭, 旭光; Xu, C. N.; Tanaka, Eiji; Tomokiyo, Yoshitsugu; Yamada, Hiroshi; Soejima, Yuji; Yamamura, Yuichi; Tsuji, Takeshi

doi:10.1143/jpsj.70.1054

Cited by 32 publications

(26 citation statements)

References 19 publications

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“…This result is consistent with the findings from the capacitance versus voltage data. Tenorite CuO shows similar relaxations near the same temperature range due to magnetic ordering transitions [18]. However , as depicted in Fig.…”

Section: Resultsmentioning

confidence: 75%

Effects of Processing Conditions on the Dielectric Properties of CaCu3Ti4O12

et al. 2005

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There have been a number of recent reports of anomalously large permittivities (ε r ≈ 10 4 ) in the material CaCu 3 Ti 4 O 12 . The dielectric spectra is characterized by a large, relatively temperature independent permittivity near room temperature which exhibits a dielectric relaxation above 100 K. The crystal structure of CaCu 3 Ti 4 O 12 can be described as pseudo-perovskite with a cubic unit cell with a lattice constant of 7.391Å. The ubiquitous occurrence of this dielectric behavior in ceramics, single crystals, and thin films suggests that the polarization is not related to a simple conducting grain/insulating grain boundary-type system. While the precise origin of the dielectric response is not entirely clear, in this work it is shown that processing conditions have a significant influence on the room temperature dielectric properties. Specifically, the permittivity and loss exhibit a strong dependence on the oxygen partial pressure and sintering time. In fact, studies of the effects of sintering time and supporting evidence from capacitance-voltage measurements conclusively show that there is no direct relationship between the permittivity and grain size, as is the case in classical boundary layer systems. Lastly, with aliovalent doping the room temperature dielectric properties can be optimized to provide a high permittivity (ε r ∼ 8,000) dielectric with relatively low loss (tan δ < 0.05 at 1 kHz).

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Section: Resultsmentioning

confidence: 75%

Effects of Processing Conditions on the Dielectric Properties of CaCu3Ti4O12

et al. 2005

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“…As to the temperature dependent intensity and linewidth, all modes present anomalies at temperatures 235 K and 215 K, which are near the T N1 and T N2 , One can understand qualitatively the most apparent change of the B g 1 Raman parameters at the phase transition temperatures. The previous magnetic study has confirmed that the super-exchange coupling is in the [-101] direction along which the Cu3-O4-Cu4 bonds have the largest angle of 146° (all other angles are nearly 90° thus very weak coupling) [8]. Because the amplitude of the superexchange interaction depends on the bond length and the bond angle, the magnetoelastic coupling effect may be observed on all of the phonon modes.…”

Section: Resultsmentioning

confidence: 88%

“…High purity powder of CuO and iodine were sealed into a quartz glass tube at high vacuum, then put into a two-zone (1223 K and 1173 K, respectively) electric furnace with the source materials at the high temperature end. By heating for 700 hours, we obtained large single crystals with dimensions up to 14 × 3 ×0.3 mm 3 [8,13].…”

Section: Methodsmentioning

confidence: 99%

“…Zheng et al found hole ordering in striped domains analogous to the charge stripes in cuprates [7], and further found that there exists a strong charge-spin-lattice coupling and a possible Cu orbital coupling contributing to the short-range antiferromagnetic interaction up to 800 K, where a charge-spin-lattice correlated phase transition featured by charge excitation, specific heat anomaly and decrease in lattice distortion was verified [8]. They also observed ferroelectric properties in this strongly magnetic-dielectric coupled material [9].…”

Section: Introductionmentioning

confidence: 97%

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Investigation of the Multiferroic Transition in CuO Single Crystal using Dielectric and Raman Spectroscopy Measurements

Dong-Dong¹,

Zheng²,

Xu³

et al. 2014

Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013)

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Dielectric constants and Raman spectra of single crystal CuO were measured at temperatures between 77 and 295 K. Through dielectric measurements, we observed dielectric anomalies at the two successive magnetic transitions 230 K and 213 K along the three crystal axes, which is in consistence with our previously reported dielectric-magnetic coupling. Beside the well-known low-temperature band in Raman spectra, which originates from a strong magnon-phonon coupling effect, the temperature dependences of the Raman shift, intensity and linewidth of the Raman modes have revealed anomalous behaviors near the magnetic transitions. The present features are considered to be correlated with the multiferroic transition in this multiferroic material.

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“…The very recent discovery that cupric oxide (CuO) is a type-II multiferroic with a high antiferromagnetic (AF) transition temperature of T N ¼230 K changed this situation drastically and opened a possible route to roomtemperature multiferroicity [6,7]. Moreover, CuO is a quasi-onedimensional (1D) magnetic system with a large magnetic coupling, J z $ 80 meV [8][9][10], which explains the high ordering temperature (T N ). In addition, upon cooling, a polar incommensurate antiferromagnetic (AF) spin-spiral ordering, referred to as AF 2 , appears below T N ¼ 230 K and a non-polar commensurate AF spin structure, AF 1 , below the lock-in temperature T L ¼213 K. Finally, the Dzyaloshinskii-Moriya (DM) 'cycloidal' interactions have been shown to have a major role in the emergence of the electric polarization in CuO [11][12][13].…”

Section: Introductionmentioning

confidence: 99%