Magnetic Properties And Thermodynamic Properties Of Mixed Spin Ising Diamond Chain

Some organic polymers and compounds of copper are abstracted into a one-dimensional diamond chain model in magnetic studies. To study magnetic property of a diamond chain has play an important role in both experiments and applications. In this paper, we establish a mixed spin Ising diamond chain model on the basis of the effective-field theory with correlations. We have investigated the magnetic properties of the ferrimagnetic/ ferromagnetic diamond chain with the co-existence of crystal field and transverse field. The formula of the magnetization and the magnetic susceptibility has been given. We write programs by matlab software to investigate effects of the various parameters, such as exchange couplings, transverse field and the anisotropy on the magnetization, the magnetic susceptibility, blocking temperature, internal energy, specific heat and hysteresis loop. Numerical calculation results of Ising diamond chain have been given.Magnetization curves of ferrimagnetic mixed spin Ising diamond chain appear step effect, the number of steps reduced with the increasing of the value of exchange couplings and the anisotropy. The average magnetization of the system decreases with the increase of the temperature. At the same temperature, with the increase of the transverse field, the value of exchange couplings and the anisotropy, the average magnetization decreases, and the average magnetization increases with the increase of the external magnetic field. The temperature dependence of magnetic suscetibility curves appear a peak, the corresponding temperature is called a blocking temperature. When the temperature is higher than blocking temperature, the system change from ferrimagnetic to superparamagnetic. Internal energy is rapidly increased as the temperature rises until the first derivative of internal energy reaches a maximum around blocking temperature, and increased slowly after the maximum. There are two peaks in a specific heat curve in a fixed parameter rang, this is due to the weaker exchange interaction and transverse field or the stronger external field. The coercivity increases with the increase of |1J |, and decreases with the increase of |1D |, 2Ω and TkB; With the changes of 1Ω, |1J |, |2D | and TkB, the hysteresis loop changes from zero circle to seven circles, and the areas of the hysteresis loop are also changed.The magnetization curves of ferromagnetic mixed spin Ising diamond chain also appear step effect, the number of steps reduced with the increase of exchange couplings, increase first and decrease later with the increase of |1D |, are great influenced by the change of |2D |. The average magnetization of the system decreases with the increase of the temperature. At the same temperature, with the increase of exchange couplings and the external magnetic field, the average magnetization increases, and the average magnetization decreases with the increase of the value of the anisotropy and external magnetic field. The temperature dependence of magnetic suscetibility curves appear a peak, the corresponding temperature is called blocking temperature. When the temperature is higher than blocking temperature, the system change from ferromagnetic to superparamagnetic. The variation of internal energy and specific heat are similar with that in ferrimagnetic system, the difference is that the weaker external field lead to two peaks in a specific heat curve. The maximum circles of the hysteresis loops are three, the number of circles in hysteresis loop increase first and decrease later with the increase of exchange interaction 1J and the anisotropy |2D |, and decrease with the increase of transverse field 1Ω and temperature TkB.The results show that magnetization curves appear step effect, and the systems have multi-circles of hysteresis loop. These properties can have potential and great application prospects in the magnetic storage materials.