Heat capacity and thermal expansion of CdCr2Se4 and CdCr2S4

Tachibana, Makoto; Taira, Naoya; Kawaji, Hitoshi

doi:10.1016/j.ssc.2011.08.029

Cited by 16 publications

(15 citation statements)

References 23 publications

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“…NTE has been found in those magnetic frustrated spinels due to the strong spin-lattice coupling. 238 For example of NTE in ZnCr 2 Se 4 spinel, the contribution of spin-lattice coupling and the coexistence of AFM and FM to NTE have been well supported by experimental studies of infrared-spectroscopy lattice dynamics and temperature dependence of neutron diffraction. Due to this competition, NTE behaviour occurs at temperatures above T N where such competition coexists in ZnCr 2 Se 4 (a l = À3.6 Â 10 À6 K À1 , 21-40 K), 188,236,237 and CdCr 2 O 4 (a l = À1.4 Â 10 À6 K À1 , 45-140 K), 187 or in the ferromagnetic phase with relatively lower T C such as CdCr 2 S 4 (a l = À1.8 Â 10 À6 K À1 , 4.2-120 K).…”

Section: Nte Magnetic Oxides and Other Materialsmentioning

confidence: 86%

“…239 Those properties are attributed to the cooperativity and competition between charge, spin, and orbital degrees of freedom, all of which are interestingly strongly coupled with the lattice. 189,238,239 Note that for those ferromagnetic spinels with higher T C , such as CdCr 2 Se 4 and HgCr 2 Se 4 , antiferromagnetic interaction is weaker, which implies weaker spin-lattice coupling. Such coupling has been explained in terms of strong competition between ferromagnetic and antiferromagnetic interactions.…”

Section: Nte Magnetic Oxides and Other Materialsmentioning

confidence: 99%

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Negative thermal expansion in functional materials: controllable thermal expansion by chemical modifications

et al. 2015

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Negative thermal expansion (NTE) is an intriguing physical property of solids, which is a consequence of a complex interplay among the lattice, phonons, and electrons. Interestingly, a large number of NTE materials have been found in various types of functional materials. In the last two decades good progress has been achieved to discover new phenomena and mechanisms of NTE. In the present review article, NTE is reviewed in functional materials of ferroelectrics, magnetics, multiferroics, superconductors, temperature-induced electron configuration change and so on. Zero thermal expansion (ZTE) of functional materials is emphasized due to the importance for practical applications. The NTE functional materials present a general physical picture to reveal a strong coupling role between physical properties and NTE. There is a general nature of NTE for both ferroelectrics and magnetics, in which NTE is determined by either ferroelectric order or magnetic one. In NTE functional materials, a multi-way to control thermal expansion can be established through the coupling roles of ferroelectricity-NTE, magnetism-NTE, change of electron configuration-NTE, open-framework-NTE, and so on. Chemical modification has been proved to be an effective method to control thermal expansion. Finally, challenges and questions are discussed for the development of NTE materials. There remains a challenge to discover a "perfect" NTE material for each specific application for chemists. The future studies on NTE functional materials will definitely promote the development of NTE materials.

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Section: Nte Magnetic Oxides and Other Materialsmentioning

confidence: 86%

Section: Nte Magnetic Oxides and Other Materialsmentioning

confidence: 99%

Negative thermal expansion in functional materials: controllable thermal expansion by chemical modifications

et al. 2015

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“…Besides from tuning the magnetic interactions, pressure can also lead to structural [18][19][20][21][22][23] , electronic 21,24,25 , and even magnetic 21 27 . A red-shift of E g was detected below T C 27 , but without any apparent complementary structural effect 5,28 . As for its high-pressure behavior, a previous x-ray diffraction (XRD) investigation up to 18 GPa at ambient temperature showed that CdCr 2 Se 4 undergoes a second-order structural transition into a tetragonal phase at ~10 GPa; no space group was assigned, however 29 .…”

Section: Introductionmentioning

confidence: 94%

Pressure-induced phase transitions in the CdCr2Se4 spinel

et al. 2016

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We have conducted high-pressure x-ray diffraction and Raman spectroscopic studies on the CdCr 2 Se 4 spinel at room temperature up to 42 GPa. We have resolved three structural transitions up to 42 GPa, i.e. the starting Fd3 m phase transforms at ~11 GPa into a tetragonal I4 1 /amd structure, an orthorhombic distortion was observed at ~15 GPa, whereas structural disorder initiates beyond 25 GPa. Our ab initio DFT studies successfully reproduced the observed crystalline-to-crystalline structural transitions. In addition, our calculations propose an anti-ferromagnetic ordering as a potential magnetic ground state for the high-pressure tetragonal and orthorhombic modifications, as compared to the starting ferromagnetic phase. Furthermore, the computational results indicate that all phases remain insulating in their stability pressure range, with a direct-to-indirect band gap transition for the Fd3 m phase taking place at 5 GPa.We attempted also to offer an explanation behind the peculiar first-order character of the Fd3 m (cubic)→I4 1 /amd (tetragonal) transition observed for several relevant Cr-spinels, i.e. the sizeable volume change at the transition point, which is not expected from space group symmetry considerations. We detected a clear correlation between the cubic-tetragonal transition pressures and the next-nearest-neighbor magnetic exchange interactions for the Crbearing sulphide and selenide members, a strong indication that the cubic-tetragonal transitions in these systems are principally governed by magnetic effects.

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“…A paradigm for this type of behaviour is provided by Cr-spinels, which exhibit many different magneticallyordered phases as a function of magnetic field [22][23][24][25][26][27][28]. Many of these systems exhibit NTE [13,29,30], including the spinel CdCr 2 O 4 in zero magnetic field [31]. This suggests that the unusual thermodynamic behaviour may have a common origin; however to date there is no general understanding of this phenomenon, or how it is linked to spin-lattice coupling.…”

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confidence: 99%

Negative Thermal Expansion in the Plateau State of a Magnetically Frustrated Spinel

et al. 2019

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We report on negative thermal expansion (NTE) in the high-field, half-magnetization plateau phase of the frustrated magnetic insulator CdCr2O4. Using dilatometry, we precisely map the phase diagram at fields of up to 30 T, and identify a strong NTE associated with the collinear halfmagnetization plateau for B > 27 T. The resulting phase diagram is compared with a microscopic theory for spin-lattice coupling, and the origin of the NTE is identified as a large negative change in magnetization with temperature, coming from a nearly-localised band of spin excitations in the plateau phase. These results provide useful guidelines for the discovery of new NTE materials. arXiv:1812.05890v2 [cond-mat.str-el]

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Heat capacity and thermal expansion of CdCr2Se4 and CdCr2S4

Cited by 16 publications

References 23 publications

Negative thermal expansion in functional materials: controllable thermal expansion by chemical modifications

Negative thermal expansion in functional materials: controllable thermal expansion by chemical modifications

Pressure-induced phase transitions in the CdCr2Se4 spinel

Negative Thermal Expansion in the Plateau State of a Magnetically Frustrated Spinel

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