Ferroelectricity in natural samples of chalcocite, Cu2S

The investigations of dielectric permittivity, optic birefringence and Raman scattering spectra for CuInP 2 (Se x S 1−x) 6 mixed crystals give evidence about rapid lowering of the temperature and smearing of first order transition between monoclinic paraelectric and ferroelectric phases at sulfur by selenium replacement. In the concentration interval x = 0.3 − 0.75 the state similar to dipole glass obviously exists. The temperature dependence of the low energy part of Raman spectra for CuInP 2 S 6 crystals and concentration transformation of these spectra in CuInP 2 (Se x S 1−x) 6 solutions leads to suggestion that the morphotropic phase transitions between monoclinic and trigonal phases can be associated with the instability of a " rigid layer " shifting mode.

Open-file report /, 1979

Cu3(CG3)2(GH)2 [249.6] Bacceleyite 2;rC2 Barite BaSG4 [7S.6] chlorice BaC12 oxide EaO. stannate BaSnG3 sulfice Bab titanate baTiG3 zirconate Ba2,r03 Bcidellite (Na,K,Mg,Ca)0.33A12(Si t Al)4G10(GH)2.nH20 Bcrlinite A1PG4 Beryl Be3Al2Si6G18 [180.6] Berylliuir, Ee [REFJ Beryllium oxide-beta EeG Biotite K2(Kg,Fe)4-6(Si,Al)8020(OH)4 Bisrcite tii2G3 Bismuth Ei (REF] SEMIMETAL Bismuth titanate bi4Ti3G12 Bismuthinite bi2S3 SEi\ICGuDUCTOR Bornite Cu5FeS4 SEMICGwbUCTOK Eor«>n-: JB [REF] Bromargyrite Agtr SEMICONDUCTOR fcromellite beO brucite i«ig(Gh)2 [247.6] bunsenite i\iiG SEMICONDUCTOR Cadmium Co [REF] Cadmium bromide CcBr2 Cadmium telluride CdTe SEMICONDUCTOR Cadmcselite CdSe SEfciICGi4bbCf .i'GR Calcite CcGG3 [194.6] Calcium Ca [REF] Calcium nitrate Ca(NG3)2 Calcium ex ice CaG (Lime) INSULATOR Calcine 1 HgCl Cancrinite (^a2Ca)4[C03/(H2G)0-3/(AlSi04)6] [432.6] Cassiterite SnG2 SEMICOi^DbCTGR Celestine SrSG4 [251.6] Celsian BaAl2Si2G6 [200.6] Cerianite CeG2 Cerium Ce [REF] Cerrusite PbCG3 Cesium Cs [REF] Cesium chloride CsCl IwSULATOR Cesium ioaide Csl IwSULATGR Chalcanthite CuSG4.5H2G Chalcccite Cu2S SEMICONDUCTOR Chaiccpyrite CUir'c:S2 SEKICG^DUCTGR Chlorargyrite AgCl ELECTLOLYTE Chlcrite Mg3(Si4G10)(CH)12.hg3(Oh)6 Chromite teGr2G4 [27KCC] Chromium Gr [REF] I1ETAL hryscberyl BeA12G4 [434.6] hrysccolla CuSiG3.2H2G innabar hgS lausthalite FbSe SEMICONDUCTOR obalt Co [REF] obaltite CcAsS obaltcus oxide CoO olemanite Ca2B6Oll,5H2O [332.6] olumbite (Fe,Mn)(Cb,Ta)206 opper Cu [REF] hETAL opper dichloride CuC12 ordierite (Mg,Fe2+)2A14Si5G18 [346.6] orundum A12O3 INSULATOR otunnite PbC12 ovellite CuS METAL ristcbalite SiG2 ryolite Na3AlF6 [263.6] ummingtonite (hg,Fe)7[GH/Si4011]2 upric sulfate monohydrate CuSO4.Ii20 uprite Cu2G SEMICONDUCTOR anburite CaB2Si208 [181.6]

We report α-Cu2V2O7 to be an improper multiferroic with the simultaneous development of electric polarization and magnetization below TC = 35 K. The observed spontaneous polarization of magnitude 0.55 µCcm −2 is highest among the copper based improper multiferroic materials. Our study demonstrates sizable amount of magneto-electric coupling below TC even with a low magnetic field. The theoretical calculations based on density functional theory (DFT) indicate magnetism in α-Cu2V2O7 is a consequence of ferro-orbital ordering driven by polar lattice distortion due to the unique pyramidal (CuO5) environment of Cu. The spin orbit coupling (SOC) further stabilize orbital ordering and is crucial for magnetism. The calculations indicate that the origin of the giant ferroelectric polarization is primarily due to the symmetric exchange-striction mechanism and is corroborated by temperature dependent X-ray studies.

Nano Letters, 2015

We explore ferroelectric properties of cleaved 2-D flakes of copper indium thiophosphate, CuInP 2 S 6 (CITP), and probe size effects along with limits of ferroelectric phase stability, by ambient and ultra high vacuum scanning probe microscopy. CITP belongs to the only material family known to display ferroelectric polarization in a van der Waals, layered crystal at room temperature and above. Our measurements directly reveal stable, ferroelectric polarization as evidenced by domain structures, switchable polarization, and hysteresis loops. We found that at room temperature the domain structure of flakes thicker than 100 nm is similar to the cleaved bulk surfaces, whereas below 50 nm polarization disappears. We ascribe this behavior to a well-known instability of polarization due to depolarization field. Furthermore, polarization switching at high bias is also associated with ionic mobility, as evidenced both by macroscopic measurements and by formation of surface damage under the tip at a bias of 4 Vlikely due to copper reduction. Mobile Cu ions may therefore also contribute to internal screening mechanisms. The existence of stable polarization in a van-der-Waals crystal naturally points toward new strategies for ultimate scaling of polar materials, quasi-2D, and single-layer materials with advanced and nonlinear dielectric properties that are presently not found in any members of the growing "graphene family".

Physical Review B, 1992

We report on three phase transformations occurring between 120 and 170 K in YBa2Cu306+" for x)0.2. It is proposed that one or two of them are due to the ordering of the 0 atoms among the offcenter positions in the Cu-0 zigzag chains. Since an electric dipole is associated to 0 ions in such offcenter positions, ferroelectric (oxygens on the same side of the chain) and antiferroelectric (oxygens on opposite sides in zigzag fashion) domains should also form. The proposed interpretation correlates well with the overall phenomenology, including an anelastic relaxation process previously interpreted in terms of the nearly uncorrelated jumps of such oxygens. The phase transition around 170 K may correspond to a ferroelectric displacive transition appearing in the dielectric function.

physica status solidi (a), 1982

physica status solidi (a), 1982

The dark current-voltage (J-U) characteristics of Cu,O crystals are measured for the first time in the temperature range between 4 and 300 K taking into account the direction of the applied electric field relative to the crystallographic directions. These J-U characteristics at low temperatures indicate the existence of potential barriers which are related to structural defects revealed by chemical etching. This view is supported by the observed anisotropy of the conductivity at low temperatures: at 4.2 K, the conductivity in the (001) direction is higher than in the (110) direction. Les caractbrist,iques courant-tension (J-U) des cristaux de Cu,O sont mesurbes pour la premiere fois dans le domaine de temperature entre 4 et 300 K en tenant compte de la direction du champ 6lectrique applique par rapport aux directions cristallographiques. Ces caracteristiques J-U B basses temperatures indiquent l'existence de barrikres de potentiel qui so nt libes aux defauts de structure rbv618s par attaque chimique. Ce point de vue est appuyb par l'anisotropie observbe dans la conductivitb B basses temperatures: It 4,2 K, la conductivitb dans la direction (001) est plus grande que dans la direction (110).

2016

The Earth’s core, mantle and crust are composed of rocks and minerals, and exhibit electrical and magnetic phenomena. Electrical data in particular are extremely sparse for Earth materials; fewer than one hundred minerals have piezoelectric data associated with them, for example. This type of data helps to constrain Earth processes and structures, such as core and mantle composition, geomagnetic anomalies, seismic electric signals, and others. In this review, two hundred seventeen minerals exhibiting ferroelectricity, pyroelectricity or piezoelectricity are presented, with quantitative data where known. Fifty-three of these are centrosymmetric, and explanations are given for their apparent violations of crystal theory. Some thermoelectric and magnetic data are also presented for minerals, and an overview of rock electricity is included. Recommendations for further study are given, as well, such as determining the dielectric behavior of rocks and minerals at depth, and testing minerals for alternative energy applications.

Journal of Solid State Chemistry, 2011

APL Materials, 2021