Explory Research Of Magnetism And Single Crystal Growth Of Two Nickel Ions Organic Ligand Compounds

Magnetic materials have important applications in life and scientific research.They are often used in the development of magnetic memory,electric motors,transformers and microwave devices.Therefore,magnetic materials have always been the focus of research in condensed matter physics.Quantum magnets can be used to study the Bose-Einstein condensates of magnons,in which bosons condense into a quantum state of the lowest energy when the temperature drops to absolute zero.This very interesting macroscopic quantum phenomenon is helpful for researchers to study the microscopic quantum mechanism.In the past few decades,the study of Bose-Einstein condensates has become very popular in optical ultra-cold atoms and condensed matter physics.Many researchers have tried to study Bose Einstein condensates using quantum magnets because the extremely low temperature experimental conditions needed to study Bose Einstein condensates using ultra-cold atoms are very demanding.This is because the mass of the boson in the quantum magnet is lighter,so the transition temperature of the Bose-Einstein condensate in the magnons is higher.And with the increase of the magnetic field,the transition temperature of the quantum magnet may even reach room temperature,so it can be used to make quantum switches and quantum devices in the future,and may even be used in quantum computing The main results of this paper are as follows:1.Single crystal of dichloro[1,2-bis(diphenylphosphino)ethane]nickel²⁺(Ni Cl₂(dppe))with nearly cm size were grown for the first time by the method of solvent evaporation.The crystallographic plane of Ni Cl₂(dppe)single crystal were determined by X-ray diffractometer at room temperature.So far,the X-ray diffraction spectra show that we have grown single crystal faces including(110),(-1-11)and(011).The magnetization(M)measurements of Ni Cl₂(dppe)single crystals were carried out on Magnetic Property Measurement System(MPMSXL)and Magnetic Property Measurement System 3(MPMS3).Firstly,the magnetism of Ni Cl₂(dppe)single crystals were measured by MPMS3 when the magnetic fields were parallel and vertical to the(110)and(-1-11)crystal planes,and the temperature range was 2 K to 300 K.Magnetization results for Ni Cl₂(dppe)exhibit two obvious contributions,anisotropic paramagnetic part and very strong diamagnetic part.After subtraction of the temperature-dependent diamagnetic contribution,the results show typical temperature-independent anisotropic paramagnetic behavior.According to its crystal structure and basic magnetic knowledge,its diamagnetism mainly comes from the benzene ring of Ni Cl₂(dppe).The anisotropic paramagnetic behavior should come from Ni²⁺ions of Ni Cl₂(dppe).Next,the ultra-low temperature magnetism of Ni Cl₂(dppe)crystal were performed with MPMSXL when the magnetic fields were parallel and vertical to the(110)crystal planes,and the temperature range was 0.5 K to 2 K.When the magnetic field is perpendicular to the(110)plane,the antiferromagnetic transition is observed,and the temperature is 0.55 K for zero field cooling and 0.61 K for field cooling.When the magnetic field is parallel to the(110)plane,no antiferromagnetic transformation is observed,indicating that the phase transition is strongly dependent on the direction of the magnetic field.At last,the ultra-low temperature specific heat of Ni Cl₂(dppe)crystal were performed with PPMS when the magnetic field was perpendicular to the(-1-11)and(110)crystal plane,and the temperature range was 0.1 K to 1 K.The magnetic field induced quantum phase transition is not observed in the results of the variation of the specific heat at very low temperature with temperature and magnetic field.2.Single crystal of nickel dibutyl dithiocarbamate with nearly cm size were grown for the first time by the method of solvent evaporation.The crystal was determined to be single crystal by X-ray diffractometer at room temperature.We call the natural growth plane of nickel dibutyl dithiocarbamate single crystal ab plane.The magnetization(M)measurements of nickel dibutyl dithiocarbamate single crystals were carried out on MPMSXL and MPMS3.Firstly,MPMS3 was used to measure the magnetic properties of nickel dibutyl dithiocarbamate single crystal when the magnetic field was parallel and vertical to the ab crystal surface of nickel dibutyl dithiocarbamate,and when the temperature range was 2 K to300 K.Magnetization results for nickel dibutyl dithiocarbamate exhibit two obvious contributions,anisotropic paramagnetic part and very strong diamagnetic part.After subtraction of the diamagnetic contribution,the results show typical anisotropic paramagnetic behavior.Such anisotropic diamagnetism should come from atoms with full shell of nickel dibutyl dithiocarbamate.The anisotropic paramagnetic behavior should come from Ni²⁺ions of nickel dibutyl dithiocarbamate.At last,the ultra-low temperature magnetism of nickel dibutyl dithiocarbamate crystal were performed with MPMSXL when the magnetic fields were parallel and vertical to the ab crystal planes,and the temperature range was 0.5 K to 2 K.When the magnetic field is parallel to the ab plane,the antiferromagnetic transition is observed,and the temperature is about 0.9 K for zero field cooling and field cooling.When the magnetic field is perpendicular to the ab plane,no antiferromagnetic transformation is observed,indicating that the phase transition is strongly dependent on the direction of the magnetic field.