High Field Modulation Effects On 2D And 3D Magnetic Coupling

As one of the important thermodynamics parameters,magnetic field is an effective measurement tool on the investigation of the physics and mechanism of materials,which has the same function as temperature and pressure to change the energy level of system.Especially the high magnetic field can not only control performance,but also measure the physical properties of materials intuitively and effectively.In this paper,a quasi-two-dimensional and two three-dimensional antiferromagnetic coupling materials are studied.The high magnetic field interacts with the magnetic anisotropy and mainpulates its anisotropic behavior,provides another important research method for exploring the magnetic structure and magnetoelectric properties of the multidimensional system.The primary contents are as follows,1.We describe the importance of high magnetic field in the research of materials science and condensed matter physics.The research progress of ThCr2Si2 magnetic materials is briefly introduced,including the research status of TlCo2Se2 single crystal with interlayer nonlinear antiferromagnetic structure.Finally,the lattice structure,magnetic structure,electronic structure and transport properties of perovskite manganese oxides are introduced.2.In order to study the tuning process of the two-dimensional magnetic coupling anisotropy under high magnetic field systematically,we developed a sample rotating probe,which can be used in the pulsed high magnetic field and the low temperature environment.Combined with digital lock-in technology,the electronic transport measurement with the weak signal was realized at any angle continuously.Based on pulsed high magnetic field,the method of strain measurement was explored and studied.And we studied spin-lattice coupling induced magnetostriction in selected two-dimensional magnetic coupling system.3.We studied the magnetic,electrical transport and strain properties of the TlCo2Se2 single crystal systematically.Significant antiferromagnetic transition occured at 88 K.The magnetization gets saturated at 17 T and 30 T,respectively,for the case that the magnetic field is perpendicular and paralleled to the c-axis,which shows significant magnetic anisotropy.Combined with the magnetization,electrical transport and strain measurement under the high magnetic field,the magnetic coupling relationship between intra-layer and inter-layer Co ions in the self-consistent and detailed complete magnetic diagram are obtained.4.We successfully fabricated high quality Nd0.45Sr0.55MnO3 single crystal samples with optical floating zone method.The magnetization measurement results show that the sample has a very significant antiferromagnetic structure at 212 K.In the study of electrical transport,the strong anisotropic electrical property was observed,but the anisotropic behavior is not significant in the magnetization measurement.5.Using Zn and Ba ions as the dopant elements,the influence of high magnetic field and A-site dopant on charge-ordered antiferromagnetic coupling of La0.5Ca0.5MnO3 was studied.The experimental design ensured that the ratio of Mn3+/Mn4+ did not change during the doping process,avoids to change its charge-ordered antiferromagnetic physical structure.In this paper,a new effective experimental approach is explored to study the charge-ordered antiferromagnetic coupling by using the combination of pulsed magnetic field and lattice distortion caused by doping.