The structural and magnetic properties of single-crystal Gd4Ga2O9

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Xunqing Yin ◽  
Yunlei Zhong ◽  
Yiming Cao ◽  
Yunlong Li ◽  
Guohua Wang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Magnetic Frustration ◽  
Floating Zone ◽  
Monoclinic Structure ◽  
Magnetic Entropy ◽  
Temperature Dependent ◽  
Capacity Curves ◽  
Structural And Magnetic Properties ◽  
Crystallographic Axes

The crystalline structures and magnetic and thermodynamic properties of a Gd4Ga2O9 single crystal grown with the optical floating zone technique have been investigated. Gd4Ga2O9 crystallizes in a monoclinic structure with the space group P21/c at room temperature. Temperature-dependent magnetic susceptibility measurements along the three crystallographic axes reveal a paramagnetic (PM) behavior between 2 and 300 K. A Curie–Weiss (CW) law fit was carried out and the CW temperature θCW and magnetic frustration parameter f were calculated; these suggest antiferromagnetic (AFM) interactions between Gd3+ spins and a strong magnetic frustration. The field dependence of the magnetization at 2 K further confirms the magnetic frustration characteristics. A distinct λ-shaped peak at 1.4 K in the heat capacity curves suggests a transition from the PM to AFM phase. The magnetic entropy is contributed solely by Gd3+ ions.

scholarly journals Colossal Negative Magnetoresistance Effect in a La1.37Sr1.63Mn2O7 Single Crystal Grown by Laser-Diode-Heated Floating-Zone Technique

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 547
Author(s):  
Si Wu ◽  
Yinghao Zhu ◽  
Junchao Xia ◽  
Pengfei Zhou ◽  
Haiyong Ni ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Single Crystal ◽  
Laser Diode ◽  
Room Temperature ◽  
Floating Zone ◽  
Magnetoresistance Effect ◽  
X Ray ◽  
Mr Effect ◽  
Distinct Features ◽  
The Magnetic Field

We have grown La 1.37 Sr 1.63 Mn 2 O 7 single crystals with a laser-diode-heated floating-zone furnace and studied the crystallinity, structure, and magnetoresistance (MR) effect by in-house X-ray Laue diffraction, X-ray powder diffraction, and resistance measurements. The La 1.37 Sr 1.63 Mn 2 O 7 single crystal crystallizes into a tetragonal structure with space group I4/mmm at room temperature. At 0 T, the maximum resistance centers around ∼166.9 K. Below ∼35.8 K, it displays an insulating character with an increase in resistance upon cooling. An applied magnetic field of B = 7 T strongly suppresses the resistance indicative of a negative MR effect. The minimum MR value equals −91.23% at 7 T and 128.7 K. The magnetic-field-dependent resistance shows distinct features at 1.67, 140, and 322 K, from which we calculated the corresponding MR values. At 14 T and 140 K, the colossal negative MR value is down to −94.04(5)%. We schematically fit the MR values with different models for an ideal describing of the interesting features of the MR value versus B curves.

scholarly journals High pO2 Floating Zone Crystal Growth of the Perovskite Nickelate PrNiO3

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 324 ◽  
Author(s):  
Hong Zheng ◽  
Junjie Zhang ◽  
Bixia Wang ◽  
Daniel Phelan ◽  
Matthew J. Krogstad ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Floating Zone ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Single Crystal Diffraction ◽  
Metal Insulator ◽  
X Ray ◽  
First Order ◽  
Correlated Electron

Single crystals of PrNiO3 were grown under an oxygen pressure of 295 bar using a unique high-pressure optical-image floating zone furnace. The crystals, with volume in excess of 1 mm3, were characterized structurally using single crystal and powder X-ray diffraction. Resistivity, specific heat, and magnetic susceptibility were measured, all of which evidenced an abrupt, first order metal-insulator transition (MIT) at ~130 K, in agreement with previous literature reports on polycrystalline specimens. Temperature-dependent single crystal diffraction was performed to investigate changes through the MIT. Our study demonstrates the opportunity space for high fugacity, reactive environments for single crystal growth specifically of perovskite nickelates but more generally to correlated electron oxides.

scholarly journals The Structure, Vibrational Spectra, and Thermal Expansion Study of AVO4 (A=Bi, Fe, Cr) and Co2V2O7

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1628 ◽  
Author(s):  
Xiaoke He ◽  
Chenjun Zhang ◽  
Ding Tian
Keyword(s):  
Thermal Expansion ◽  
Room Temperature ◽  
Coefficient Of Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Monoclinic Structure ◽  
Functional Material ◽  
Temperature Dependent ◽  
Vanadium Compounds ◽  
Measurement Results ◽  
Thermal Expansion Study

Vanadate is an important functional material. It has been widely studied and applied in luminescence and photocatalysis. Vanadium compounds have been synthesized to investigate the thermal expansion properties and structure. Both BiVO4 and Co2V2O7 are monoclinic at room temperature, FeVO4’s crystal structure is triclinic, and CrVO4 is orthorhombic. The relatively linear, thermal-expansion, and temperature-dependent Raman spectroscopy results showed that the phase transition of BiVO4 occurred at 200 to 300 °C. The coefficient of thermal expansion (CTE) of Co2V2O7 was larger than that of the monoclinic structure BiVO4. The CTE of the tetragonal structure of BiVO4 was 15.27 × 10−6 °C−1 which was the largest CTE in our measurement results, and the CTE of anorthic structure FeVO4 was 2.84 × 10−6 °C−1 and was the smallest.

scholarly journals A novel crystal polymorph of volborthite, Cu3V2O7(OH)2·2H2O

2012 ◽  
Vol 68 (7) ◽  
pp. i41-i44 ◽  
Author(s):  
Hajime Ishikawa ◽  
Jun-ichi Yamaura ◽  
Yoshihiko Okamoto ◽  
Hiroyuki Yoshida ◽  
Gøran J. Nilsen ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Single Crystal ◽  
Room Temperature ◽  
Magnetic Interactions ◽  
Water Molecules ◽  
Monoclinic Structure ◽  
Space Group ◽  
X Ray

A new polymorph of volborthite [tricopper(II) divanadium(V) heptaoxide dihydroxide dihydrate], Cu3V2O7(OH)2·2H2O, has been discovered in a single crystal prepared by hydrothermal synthesis. X-ray analysis reveals that the monoclinic structure has the space groupC2/cat room temperature, which is different from that of the previously reportedC2/mstructure. Both structures have Cu3O6(OH)2layers composed of edge-sharing CuO4(OH)2octahedra, with V2O7pillars and water molecules between the layers. The Cu atoms occupy two and three independent crystallographic sites in theC2/mandC2/cstructures, respectively, likely giving rise to different magnetic interactions between CuIIspins in the kagome lattices embedded in the Cu3O6(OH)2layers.

Acoustic Properties of Ho2Si2O7 Single Crystal Investigated by Brillouin Light Scattering

2012 ◽  
Vol 510-511 ◽  
pp. 143-147
Author(s):  
Ghulam Shabbir ◽  
Asghari Maqsood ◽  
Izhar-ul-Haq
Keyword(s):  
Light Scattering ◽  
Elastic Constant ◽  
Single Crystal ◽  
Room Temperature ◽  
Acoustic Properties ◽  
Temperature Dependent ◽  
Hypersonic Velocity ◽  
Brillouin Light Scattering ◽  
Dependent Behavior ◽  
Small Dispersion

Micro-Brillouin light scattering experiments were performed on flux grown D-type (monoclinic, P21/c) Ho2Si2O7 single crystal from room temperature to 850 K. Both the hypersonic velocity (VLA) and related elastic constant (c33) of the longitudinal acoustic phonons propagating along 001-direction showed a small dispersion at T565 K whereas the same could not be observed clearly in attenuation/damping. The overall temperature dependent behavior of elastic constant and hypersonic velocity was attributed to the lattice anharmonicity of the crystal in the investigated temperature range.

Electron Paramagnetic Resonance Study of Cu 2+ in CdCa (CH3COO) 4 • 6H2O Single Crystal

2000 ◽  
Vol 55 (8) ◽  
pp. 729-732
Author(s):  
Hüsey in Kalkan ◽  
Ismet Senel
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystal ◽  
Room Temperature ◽  
Electron Paramagnetic Resonance Study ◽  
Temperature Dependent ◽  
Paramagnetic Resonance ◽  
Jahn Teller ◽  
Experimental Errors ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

Abstract The Electron Paramagnetic Resonance spectra of Cu 2+ in CdCa (CH3COO)4 • 6H2O (cadmium calcium tetraacetate hexahydrate) powder and single crystal have been recorded at 300 and 133 K. The angular variation of the spectra indicated the substitution of the host Cd 2+ with Cu 2+ . The observed values of the g and A hyperfine tensors were found to be temperature dependent, and this dependence is discussed and explained on the basis of dynamic Jahn-Teller effects. The spin-Hamiltonian parameters were found to be axial symmetric at room temperature, whereas they showed deviations from axial symmetry at low temperature. The g and A tensors where found to be coaxial within the limits of experimental errors, and the ground state wave functions of the complex at 300 and 133 K have been constructed.

scholarly journals Temperature-dependent optical phonon behaviour of a spinel Zn2TiO4 single crystal grown by the optical floating zone method in argon atmosphere

RSC Advances ◽  
2017 ◽  
Vol 7 (56) ◽  
pp. 35477-35481 ◽  
Author(s):  
Liang Li ◽  
Shuohui Gao ◽  
Tian Cui ◽  
Benxian Li ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Raman Spectra ◽  
Optical Phonon ◽  
Argon Atmosphere ◽  
Floating Zone ◽  
Temperature Dependent ◽  
Zone Method ◽  
Floating Zone Method ◽  
First Time

The spinel Zn2TiO4 single crystals were grown via optical floating zone technology in an argon atmosphere for the first time. And temperature dependent Raman spectra were presented.

Optical properties of trirutile structure MgTa2O6 single crystals grown by optical floating zone method

2020 ◽  
Vol 34 (26) ◽  
pp. 2050281
Author(s):  
Litong Huang ◽  
Qiang Zhou ◽  
Fangfei Li ◽  
Liang Li
Keyword(s):  
Optical Properties ◽  
Single Crystals ◽  
Room Temperature ◽  
Floating Zone ◽  
Temperature Dependent ◽  
Zone Method ◽  
Floating Zone Method ◽  
Research Objects ◽  
Absorbance Spectra ◽  
Temperature Dependent Photoluminescence

[Formula: see text] single crystals with trirutile structure have been employed as research objects in this paper. The absorbance spectra of the [Formula: see text] crystals are presented and the optical bandgap structures of [Formula: see text] are discussed. Both room temperature and temperature-dependent photoluminescence (PL) of [Formula: see text] single crystals are investigated. Significantly, there are two processes in the emission, and the optical phonon participated procedures are observed and described.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

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