Monte Carlo Study of the Phase Diagrams of a Ferri

Authors: A Feraoun A Zaim M Kerouad

Publish Date: 2016/01/16

Volume: 29, Issue: 4, Pages: 971-980

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Abstract

A Monte Carlo simulation based on Metropolis algorithm has been used to investigate the magnetic properties of an Ising ferrimagnetic nanowire on a hexagonal structure which is made up with L alternate layers of spins σ = ±3/2 ±1/2 and S = ±1 0 The critical behaviors are studied in the absence as well as in the presence of crystal field interactions The obtained results show the existence of some interesting phenomena such as the appearance of different types of phase diagrams Furthermore tricritical point isolated critical point critical end point and compensation behavior are found for appropriate values of the system parametersRecently nanoparticles 1 2 3 nanofilms 4 5 6 nanotubes 7 and nanowires 8 9 10 11 12 have attracted considerable attention The motivation in these studies is mainly because nanomaterials have many peculiar physical properties compared with those of bulk materials There are many potential applications where nanomaterials may become very important such as in information storage sensors 13 and medical applications 14 Under certain conditions there is in ferrimagnets an interesting possibility of the existence of the compensation temperature The compensation behavior has potential applications in the field of thermomagnetic recording 15 16 17 Significantly the coercivity has been proven to show strong temperature dependence near the compensation point It can be applied to achieve a direct erasable ability with a local heating by a focused laser beam in magnetic optical recording media 18 19The nanomaterials have been studied both experimentally and theoretically within various models and techniques rich critical and magnetic properties were found In refs 20 21 the magnetic properties of a cubic nanowire a multilayer and multisublattice cubic nanowire with mixed spin 13/2 have been examined by the effective field theory EFT It was found that two compensation points can exist for certain values of the system parameters In ref 22 the authors have studied the magnetic behavior of a mixed spin 13/2 ferrimagnetic spherical nanoparticle using Monte Carlo simulations The results found present rich variety of phase diagrams with firstorder and secondorder phase transitions By using Monte Carlo simulations 23 the dynamic phase transition properties of a single spherical ferrimagnetic coreshell nanoparticle have been investigated It has been found that the dynamic phase boundaries strongly depend on the Hamiltonian parameters such as the high amplitude and the period of the external field In ref 24 the authors have investigated the magnetic properties of the cubic nanowire which consists of a ferromagnetic core of spin1 atoms and a ferromagnetic shell of spin −3/2 atoms with ferrimagnetic interface coupling using the effectivefield theory with correlationsEFT They have found that two compensation points can appear for appropriate values of the system parameters In ref 25 the phase diagrams and compensation behaviors of a mixed spin 1/21 hexagonal Ising nanowire with coreshell structure have been studied by using the effectivefield theory with correlations It has been found that the system shows many rich phenomena such as firstorder and secondorder phase transitions and tricritical points Recently in ref 26 Monte Carlo simulation has been used to study the magnetic properties of a mixed spin 5/22 ferrimagnetic Ising model on a honeycomb lattice The system displays very rich critical behaviors including the first and secondorder phase transitions the tricritical points and the compensation points Using a continuum approach the magnetic configurations of barcodetype magnetic nanostructures consisting of alternate ferromagnetic and nonmagnetic layers arranged within a multilayer nanotube structure are investigated in ref 27 The authors found that the lines separating the magnetic phases and in particular the triple point are very sensitive to the geometry of the barcodetype nanostructures Experimentally magnetic NiFe/Au barcode nanowires with selfpowered motion is investigated 28 The approach used of synthesize these nanowire demonstrates how sophistication in barcode nanoarchitecture can be used to synthesize a wide range of hybrid materialsDespite these studies as far as we know the phase diagrams and the compensation behavior of a mixed spin 3/21 hexagonal Ising nanowire with alternate layers have not been investigated Given their potential technological applications linked with the existence of a compensation phenomena nanowires with alternate layers have been attracted considerable interest Therefore in this paper we have used Monte Carlo simulations to study the phase diagrams of a hexagonal ferrimagnetic nanowire with alternate layers structure consisting of σlayers with the spin σ = 3/2 and Slayers with the spin S = 1 The outline of the paper is organized as follows in Section 2 we briefly present our model and the related formulation The results and discussions are presented in Section 3 and finally Section 4 is devoted to our conclusionsIn this section we will discuss the thermal and magnetic properties of the system for some selected values of the Hamiltonian parameters Throughout the simulation we have tacked L = 200 the total number of layers and each layer of the nanowire consists four rings A number of additional simulations were performed for L = 250 and L = 300 but no significant differences were found from the results presented here

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