Study Of The Physical Properties Of Magnetic Nanoisland

Low-dimensional Nanomaterials is one of the hotspots in current study,including two-dimensional,one-dimensional and zero dimensional nanomaterials.On the material structure,the zero dimensional nanomaterials can be represented as quantum dots,nanoisland and so on.Nanoisland is composed of limited atoms and known as “artificial atoms”,which the x-y plane and z direction are in the nanometer order.Compared with other magnetic materials,nanoisland can significantly improve the specific surface area.It may apply to magnetic storage device,small structure and high coverage of solar cells,lithium ion battery and photoelectric detectors,etc.The applications of nanoisland have potential prospects.Therefore,the theoretical results may have guiding significance for application.The physical characteristics of hexagonal prismatic nanoisland are examined by using the effective-field theory with correlations.Curves of magnetizations,magnetic susceptibilities,phase diagrams,hysteresis loop,step effect,internal energy and specific heat of the system on physical parameters are obtained and discussed in detail.It shown that the reentrant phenomenon has been observed with the variation of exchange interaction,single-ion anisotropies and transverse fields.The phase temperature corresponding to the inflection point of the internal energy changes for various parameters.The specific heat curve exhibits a shape peak at the transition temperature which is the typical second-order phase transition.The magnetization appear obvious magnetization plateaus within the longitudinal magnetic field when the system at low temperature.The surface exchange interaction and single-ion anisotropies play important roles in step effect.The shape and number of the hysteresis loop can be changed depending on the value of exchange coupling,single-ion anisotropy and temperature.The physical characteristics of hexagonal and square nanoisland are also examined by using the effective-field theory with correlations.The magnetization,phase temperature and step effect of the square nanoisland are great influenced by single-ion anisotropy in the core.Similar to the changing rules of hexagonal nanoisland,multi-transition points present in the system with various parameters.The changing laws of the internal energy,specific heat curves are also similar to hexagonal nanoisland.At low temperature,the system appear magnetization plateaus and multi-loop hysteresis loop.