Temperature Dependence of Electrical Properties and Phase Transition Characteristics of [001]‐Oriented Rhombohedral Mn‐0.15PIN‐0.55PMN‐0.30PT Single Crystal

The electrical properties of [001]-oriented morphotropic phase boundary (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-33%PT) single crystal have investigated as a function of temperature and frequency. The ac-conductivity exhibited continuous dispersion at all temperatures and frequency range examined and was associated to the thermally activated space charge carriers and local off-centering of Ti4+ and Pb2+ ions. The variations in ferroelectric phase transition temperatures observed in the poled state were associated to the polarization fluctuations and phase co-existence.

Download Full-text

Crystal Structure and Dielectric Property of Endohedral Lithium Fullerene

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314098040 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C195-C195

Author(s):

Shinobu Aoyagi ◽

Kunihisa Sugimoto ◽

Hiroshi Okada ◽

Norihisa Hoshino ◽

Tomoyuki Akutagawa

Keyword(s):

Crystal Structure ◽

Phase Transition ◽

Dielectric Property ◽

Low Temperature ◽

Dielectric Permittivity ◽

Single Crystal ◽

Temperature Dependence ◽

Structure Analysis ◽

X Ray ◽

Dielectric Phase

Endohedral lithium fullerene Li+@C60 can have a dielectric polarization by the off-centered location of the Li+ cation inside the C60 cage. The x-ray structure analysis of the PF6– salt [Li@C60](PF6) revealed that the Li+ cation occupies two off-centered equivalent positions at 20 K and hence the crystal is non-polar [1]. The disordered structure at low temperature is explained by a static orientation disorder of polar Li+@C60 cations and/or a dynamic tunneling of the Li+ cation inside the C60 cage. The Li+ tunneling would be suppressed by an intermolecular interaction at lower temperature and a dielectric phase transition might be induced. We reveal the dielectric property and crystal structure of [Li@C60](PF6) below 20 K in this study. The temperature dependence of the dielectric permittivity was measured for the single crystal down to 9 K. The dielectric permittivity increases with decreasing temperature according to the Curie-Weiss law. Such a behavior was also observed in H2O@C60 crystal but not in empty C60 crystal [2]. No dielectric phase transition was observed in H2O@C60 down to 8 K. In contrast, a dielectric anomaly suggesting a phase transition was observed in [Li@C60](PF6) around 18 K. The single-crystal x-ray diffraction experiment below 20 K was also performed at SPring-8 BL02B1. The crystal has a cubic structure at 20 K [1]. The temperature dependence of the cubic lattice constant shows no anomaly around 18 K. However, diffraction peaks that are forbidden for the given structure appear below 18 K. Thus the crystal symmetry is lowered by the dielectric phase transition. We present the result of the crystal structure analysis of the newly discovered low-temperature phase.

Download Full-text

Electrical Properties of GaAs Implanted with High Energy (100meV) 28Si and 120Sn Ions

ARID International Journal for Science and Technology ◽

10.36772/arid.aijst.2021.484 ◽

2021 ◽

pp. 77-92

Author(s):

يوسف بيار علي ◽

سلوان كمال جميل العاني ◽

بريج موهن ارورا

Keyword(s):

Electrical Properties ◽

Single Crystal ◽

Temperature Dependence ◽

Annealing Treatment ◽

High Energy ◽

Strong Nonlinearity ◽

Conduction Mechanisms ◽

Gaas Substrates ◽

Current Voltage ◽

Back Ward

Single crystal n-GaAs substrates have been implanted at 300 K with 100 MeV 28Si and 120Sn ions to a dose of 1x1018ions/m2 independently. The electrical properties of these samples has been investigated and compared after implantation and annealing up to 850 °C by current voltage (I-V) measurements. It has been observed that the I-V curves for the samples implanted with 28Si ions show p-n junction like characteristics which then show a linear I-V characteristics for the annealing treatment between 150-550 °C. Annealing the samples at 650 °C results in a typical diode like I-V characteristics which become less non-linear after further annealing at 750 °C. Further annealing at 850 °C results in to a back ward diode like behavior. However the I-V curves for the samples implanted with 120Sn ions and annealed up to 450C were linear which then show a weak non linearity for the annealing treatments between 550C-750C. After 850C annealing the samples show a strong nonlinearity typical of a p-n junction. The temperature dependence of resistance of both 28Si and 120Sn implanted GaAs samples after implantation and different annealing steps are investigated and the possible conduction mechanisms are discussed.

Download Full-text

Permittivity and Microstructure of (Ba,Sr)TiO3 Films: Temperature and Electric Field Response

MRS Proceedings ◽

10.1557/proc-603-233 ◽

1999 ◽

Vol 603 ◽

Cited By ~ 1

Author(s):

Yu.A. Boikov ◽

T. Claeson ◽

Z. Ivanov ◽

E. Olsson

Keyword(s):

Phase Transition ◽

Dielectric Permittivity ◽

Electric Field ◽

Single Crystal ◽

Temperature Dependence ◽

Transition Point ◽

Phase Transition Point ◽

Bulk Single Crystal ◽

Temperature Range ◽

Field Response

AbstractEpitaxial heterostructures (001)(Y,Nd)Ba2Cu3O7-δ∥(100)SrTiO3∥(001)(Nd,Y)Ba2Cu3O7-δ,(100)SrRuO3∥(100)Ba0.8Sr0.2TiO3∥(100)SrRuO3, (100)SrRuO3∥(100)SrTiO3∥(100)SrRuO3 and (100)SrTiO3∥(001)YBa2Cu3O7-δ have been grown by laser ablation. There was only a small difference of the dielectric permittivity, in the temperature range 180-300K, between a bulk single crystal and an epitaxial (100)SrTiO3 layer inserted between either high-Tc superconducting or SrRuO3 electrodes. At T<1 50K, on the other hand, the response of the dielectric permittivity of the SrTiO3 layer on temperature or electric field depended to a large extent upon the materials used as bottom and top electrodes in the heterostructures. The temperature dependence of the dielectric permittivity for the SrTiO3 layer in (100)SrRuO3∥(100)SrTiO3∥(100)SrRuO3 was well extrapolated by a Curie-Weiss relation in the range of T=80-300K, with about the same Curie constant (C0=7.5 × 104 K) and Curie temperature (TCurie=21K) as in a bulk single crystal. At temperatures higher the phase transition point (65 K), the electric field response of the permittivity of the SrTiO3 layer between high-TC superconducting or metallic oxide electrodes was well extrapolated by the same relation used for a bulk single crystal. The smallest loss factor, tanδ, was measured for the capacitance (100)SrRuO3∥(100)SrTiO3∥(100)SrRuO3 (T ≈ 50-300K, f=100kHz). The measured conductance G for the SrTiO3 layer in the (001)(Y,Nd)Ba2Cu3O7-δ heterostructure fitted well the relation InG∼-(ED/kT), with ED=0.08-0.09 eV in a temperature range close to 300K. Pronounced hysteresis was observed in the temperature dependence of the dielectric permittivity for the (100)Ba0.8Sr0.2TiO3 layer at temperatures close to the phase transition point, like in the case of a bulk single crystal. The permittivity of the (100)Ba0.8Sr0.2TiO3 layer decreased more than 50% when an electric field of 2.5×106V/m (T ≈ 300K, f=100 kHz ) was applied.

Download Full-text