检索结果-南通市图书馆

critical behavior in the layered organic–inorganic hybrid(CH3NH3)2CuCl4

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第6期29卷 487-493页

作者： Tina Raoufi Yinina Ma Young Sun Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China

The critical properties and the nature of the ferromagnetic–paramagnetic phase transition in the 2D organic-inorganic hybrid(CH3NH3)2 CuCl4 single crystal have been investigated by dc magnetization in the vicinity of the magnetic transition. Different techniques were used to estimate the critical exponents near the ferromagnetic–paramagnetic phase transition such as modified Arrott plots, the Kouvel–Fisher method, and the scaling hypothesis. Values of β = 0.22, γ = 0.82, and δ = 4.4 were obtained. These critical exponents are in line with their corresponding values confirmed through the scaling hypothesis as well as the Widom scaling relation, supporting their reliability. It is concluded that this 2D hybrid compound possesses strong ferromagnetic intra-layer exchange interaction as well as weak interlayer ferromagnetic coupling that causes a crossover from 2D to 3D long-range interaction.

关键词： critical behavior critical exponent organic-inorganic hybrid

critical behavior in Nuclear Structure from Spherical to γ-Soft Deformed Shape in IBM

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第4期47卷 705-710页

作者： ZHANG Jin-Fu LU Li-Jun BAI Hong-Bo Department of Physics Chifeng College Chifeng 024001 China

Comparing with the predictions of the transitional dynamical symmetry E（5） proposed by Iachello [Phys. Rev. Lett. 85 （2000） 3580], the critical behaviors from U（5）-0（6） are studied in the space of two control parameters in the interacting boson model. A simple shape phase diagram has been presented. It is found that E（5） predictions cannot be exactly reproduced by our calculations and that the best agreement is close to the calculations with boson number N = 9. By comparing with experimental data on E（5）-like nuclei, we find that E（5） predictions and IBM calculations can reproduce the energy ratios and E2 transition ones.

关键词： nuclear structure critical behavior E(5) nuclei IBM

Phase transition and critical behavior of spin–orbital coupled spinel ZnV_2O_4

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第1期25卷 736-741页

作者：王理王蓉娟朱媛媛卢志红熊锐刘雍石兢 Key Laboratory of Artificial Micro-and Nano-structures of Ministry of Education and School of Physics and Technology Wuhan University High Magnetic Field Laboratory Chinese Academy of Sciences School of Materials and Metallurgy Wuhan University of Science and Technology

We present the temperature-dependent susceptibility and specific heat measurement of spinel ZnV204. The structural transition with orbital ordering and the antiferromagnetic transition with spin ordering were observed at 50 K and 37 K, respectively. By analysis of the hysteresis behavior between the specific heat curves obtained in warming and cooling processes, the structural transition was confirmed to be the first-order transition, while the antiferromagnetic transition was found to be of the second-order type. At the structural transition, the latent heat and entropy change were calculated from the excess specific heat, and the derivative of pressure with respect to temperature was obtained using the Clausius--Clapayron equation. At the magnetic transition, the width of the critical fluctuation region was obtained to be about 0.5 K by comparing with Gaussian fluctuations. In the critical region, the critical behavior was analyzed by using renormalization-group theory. The critical amplitude ratio A＋/A- = 1.46, which deviates from the 3D Heisenburg model; while the critical exponent a is -0.011, which is close to the 3D XY model. We proposed that these abnormal critical behaviors can be attributed to strong spin-orbital coupling accompanied with the antiferromagnetic transition. Moreover, in the low temperature range （2-5 K）, the Fermi energy, the density of states near the Fermi surface, and the low limit of Debye temperature were estimated to be 2.42 eV, 2.48 eV-1, and 240 K, respectively.

关键词： spinel compounds specific heat phase transition critical behavior

Magnetic Field Effect on critical behavior of Perovskite Ferromagnet

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2005年第5期23卷 534-536页

作者：田宏伟郑伟涛陈燕萍丁涛王欣阚东武 Department of Materials Science and Key Laboratory of Automobile Materials of MOE Jilin University Changchun 130012 China School of Chemistry Jilin University Changchun 130012 China

The polycrystalline samples of La2/3Ca1/3MnO3 were prepared by a conventional solid state reaction method. The magnetizations （ZFC, FC and initial magnetization） of the polycrystalline La2/3Ca1/3MnO3 were measured with superconducting quantum interference device magnetometer. The scaling theory was employed to study the changes of critical behavior arising from the applied external field. The critical parameter β decreases with increasing the external magnetic field results in an increase in the magnitude of ferromagnetic ordering.

关键词： critical behavior perovskite ferromagnet manganite rare earths

critical behavior in Nuclear Structure from Spherical to y-Soft Deformed Shape in IBM

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第4期 705-710页

作者： ZHANG Jin-Fu Lü Li-Jun BAI Hong-Bo Department of Physics,Chifeng College,Chifeng 024001,China Department of Physics Chifeng CollegeChifeng 024001China

Comparing with the predictions of the transitional dynamical symmetry E(5)proposed by Iachello[***.85(2000)3580],the critical behaviors from U(5)-O(6)are studied in the space of two control parameters inthe interacting boson model.A simple shape phase diagram has been *** is found that E(5)predictions cannotbe exactly reproduced by our calculations and that the best agreement is close to the calculations with boson numberN=*** comparing with experimental data on E(5)-like nuclei,we find that E(5)predictions and IBM calculationscan reproduce the energy ratios and E2 transition ones.

关键词： nuclear structure critical behavior E(5)nuclei IBM

The critical behavior of shear modulus in solid-liquid mixing phase

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2007年第6期50卷 742-746页

作者： RAN XianWen TANG WenHui TAN Hua DAI ChengDa Institute of Technological Physics College of ScienceNational University of Defense TechnologyChangsha 410073China Laboratory for Shock Wave and Detonation Physics Research Institute of Fluid PhysicsChinese Academy of Engineering Physics(CAEP)Mianyang 621900China

The behavior of shear modulus in solid-liquid mixing phase has been discussed and analyzed. The result was concluded that shear modulus went to zero as the melting mass ratio attained a critical value. The percolation theory model we pro-posed showed that this value was about 0.68742. The melting-induced destabilizing factor of material proposed by us can represent phenomenologically the change of shear modulus in melting process.

关键词： solid-liquid mixing phase critical behavior shear modulus destabilizing factor

Influence of Inhomogeneity on critical behavior of Earthquake Model on Random Graph

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2006年第2X期46卷 261-264页

作者： ZHANG Duan-Ming SUN Fan YU Bo-Ming PAN Gui-Jun YIN Yah-Ping LI Rui SU Xiang-Ying Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

We consider the earthquake model on a random graph. A detailed analysis of the probability distribution of the size of the avalanches will be given. The model with different inhomogeneities is studied in order to compare the critical behavior of different systems. The results indicate that with the increase of the inhomogeneities, the avalanche exponents reduce, i.e., the different numbers of defects cause different critical behaviors of the system. This is virtually ascribed to the dynamical perturbation.

关键词： self-organized criticality earthquake model critical behavior power-law finite size scaling random network

Magnetic transition and large reversible magnetocaloric effect in EuCu_(1.75)P_2 compound

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2013年第2期22卷 460-463页

作者：霍德璇廖罗兵李领伟李妙钱正洪 Institute of Materials Physics Hangzhou Dianzi University Center for Integrated Spintronic Device Hangzhou Dianzi University

The magnetocaloric effect（MCE） in EuCu1.75P2 compound is studied by the magnetization and heat capacity *** and modified Arrott plots indicate that the compound undergoes a second-order phase transition at TC ～ 51 K.A large reversible MCE is observed around *** values of maximum magnetic entropy change（-△SxMma） reach 5.6 J·kg^-1·K-1 and 13.3 J·kg^-1·K-1 for the field change of 2 T and 7 T,respectively,with no obvious hysteresis loss in the vicinity of Curie *** corresponding maximum adiabatic temperature changes（△Tadmax） are evaluated to be 2.1 K and 5.0 *** magnetic transition and the origin of large MCE in EuCu1.75P2 are also discussed.

关键词： EuCu1.75P2 compound magnetocaloric effect magnetic transition critical behavior

Observation of quadratic magnetoresistance in twisted double bilayer graphene

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第10期31卷 273-277页

作者： Yanbang Chu Le Liu Yiru Ji Jinpeng Tian Fanfan Wu Jian Tang Yalong Yuan Yanchong Zhao Xiaozhou Zan Rong Yang Kenji Watanabe Takashi Taniguchi Dongxia Shi Wei Yang Guangyu Zhang Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China Research Center for Functional Materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan

Magnetoresistance(MR) provides rich information about Fermi surface, carrier scatterings, and exotic phases for a given electronic system. Here, we report a study of the magnetoresistance for the metallic states in twisted double bilayer graphene(TDBG). We observe quadratic magnetoresistance in both Moiré valence band(VB) and Moiré conduction band(CB). The scaling analysis shows validity of Kohler's rule in the Moiré valence band. On the other hand, the quadratic magnetoresistance appears near the halo structure in the Moiré conduction band, and it violates Kohler's rule, demonstrating the MR scaling related to band structure in TDBG. We also propose an alternative scaling near the halo structure. Further analysis implies that the observed quadratic magnetoresistance and alternative scaling in conduction band are related to the halo boundary. Our results may inspire investigation on MR in twisted 2D materials and provide new knowledge for MR study in condensed matter physics.

关键词： twisted double bilayer graphene Kohler's rule magnetoresistance scaling critical behavior