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In this paper, the ferrimagnetic mixed-spin (3/2, 5/2) Ising model was established to investigate the magnetic and thermodynamic properties of a nanoisland bilayer system with graphene-like structure by Monte Carlo simulation. We have analyzed the magnetization of the system and two sublattices, susceptibility, internal energy and hysteresis loops in detail. We have obtained the phase diagrams of the blocking temperature T B affected by the effects of various physical parameters. The triple hysteresis behavior has been observed, which originates from the competition among various physical parameters. Our results are comparable with those of other theoretical and experimental research. • The ferrimagnetic mixed-spin (3/2, 5/2) graphene-like nanoisland bilayer in the longitudinal magnetic field has been investigated. • Magnetization, susceptibility and internal energy have been discussed. • The phase diagrams of blocking temperature have been obtained under the influence of various physical parameters. • The triple hysteresis behavior have been found for certain physical parameters. [ABSTRACT FROM AUTHOR]

Abstract Using the dynamicMonte Carlo (DMC) simulation, the dynamic magnetocaloric effect of a ferrimagnetic C 70 Fullerene-like structure is studied within the dynamic Ising model under of a magnetic (h(t)) field. The influences of the amplitude (h 0) and the frequency (ω) of the h(t) magnetic field and bias field (h b) on the thermal behavior of the dynamic order parameter and the dynamic magnetocaloric properties (the dynamic isothermal Δ S iso (T , h (t)) entropy variation and the dynamic Δ T ad (T , h (t)) adiabatic variation of temperature), the dynamic specific heat, the dynamic entropy and as well as the dynamic refrigerant capacity (RC(t)) ferrimagnetic C 70 Fullerene-like structure are studied. Our results may be a reference for future experiment and theoretical studies of the nano-clusters. Highlights • The mixed spin-(3/2, 5/2) Ising C 70 Fullerene system is investigated. • The dynamic Monte Carlo simulation is used. • The dynamic heat specific is given. • The magnetic change entropy and the adiabatic temperature change are deduced. • The refrigerant capacity for a several dynamic magnetic field has been obtained. [ABSTRACT FROM AUTHOR]

Abstract Based on the Ising model, the magnetic and thermodynamic properties of a ferrimagnetic mixed-spin (1/2, 1, 3/2) nanoisland with a double-layer quadrangle core-shell structure has been investigated by Monte Carlo simulation. The magnetization of the total system and three sublattices, susceptibility, blocking temperature, internal energy and hysteresis loops have been discussed in detail. The phase diagrams of the T B under the influence of various parameters have been given. We have obtained the critical exponents β and γ for the system. Multiple hysteresis loops behaviors such as single, triple, quintuple and septuple loops have been found, originating from the competitions among various parameters. The results are comparable with some theoretical and experimental studies given in advance. Highlights • The ferrimagnetic mixed-spin (1/2, 1, 3/2) nanoisland in the longitudinal magnetic field has been investigated. • Magnetization, susceptibility, internal energy and blocking temperature have been discussed. • The multiple hysteresis behaviors such as single, triple, quintuple and septuple loops have been obtained. [ABSTRACT FROM AUTHOR]

Compensation temperature T comp and transition temperature T C have significant applications for the experimental realization of magnetic nanotube structure in the field of thermal magnetic recording. In this work, we use the Monte Carlo simulation to investigate the phase diagrams, magnetizations, susceptibilities, internal energies, specific heats and hysteresis behaviors of a cylindrical ferrimagnetic nanotube with core-shell structure. The effects of the single-ion anisotropies ( D C , D S ) and the exchange couplings ( J int , J S ) on the magnetic and thermodynamic properties of the system are examined. A number of characteristic behaviors are discovered in the thermal variations, depending on different physical parameters. In particular, the triple hysteresis loops behavior has been found for appropriate physical parameters. These findings are qualitatively in good agreement with related experimental and the other theoretical results. [ABSTRACT FROM AUTHOR]

The behavior of saturation magnetization as a function of temperature ( M S (T)), in Zinc doped YIG nanoparticles was investigated. The samples, with crystallite size between 40 nm and 78 nm were synthesized by the sol–gel method. With the data obtained through the vibrating sample magnetometry, an adjustment with the Approach law to obtain the saturation magnetization at temperatures between 50 K and 300 K was performed. With the data it was possible to get the M S × T experimental plots. Curves were fitted with the most recent proposal by Cojocaru et al., where an expression for M (T) is derived using a three-dimensional generalization of Heisenberg's Hamiltonian, that take into account geometry, size and boundary conditions of magnetic nanoparticles. A good correspondence was obtained between the experimental data and the adjustment through the proposal. Analyzing the parameters obtained through the fitting, it was possible to visualize a weakening in the ferrimagnetic coupling with increased doping of Zn. It was also possible to see a good adjustment of the proposal with the change in the nanoparticles shape. The proposal proved to be very useful for the study of the nanoparticles. • The Cojocaru's proposal proved to be a good tool for the study of magnetic nanoparticles. • Capture changes due to the atomic disorder caused by doping. • The type of contour condition in the particles is complex according to the system. [ABSTRACT FROM AUTHOR]

In this theoretical study, we predict the (111), (001), and (110) Mn 3 P compounds with a DO 3 -Type-structure. We first calculated the stability, and surface effects on the pure terminations of Mn 3 P (111), (001), and (110) surfaces using first-principle computations. Pure (111), (110), as well as the Mn 2 -(001) terminations, lose their half-metallic (HM) ferrimagnetic property, with higher spin polarization (SP) (75%) for Mn 2 -(111) than for the other terminations. These terminations present metallic properties because the spin-up and spin-down pass the Fermi level (є F). The Mn 1 –P termination remained HM with full SP; this is because of the strong coupling between the surface and subsurface, which indicates that this surface is a typical candidate for spin devices. The spin magnetic moments (SMMs) were investigated in all surface states. The SMM values of the central layers of the (111), (001), and (110) terminations were similar to those in the bulk, while the SMMs in the surface layer were higher than those in the bulk Mn 3 P. • The (111), (001), and (110) Mn 3 P compounds with a DO 3 -Type-structure were calculated. • The Mn 1 –P termination remained HM with full SP. • The SMM values of the central layers of the (111), (001), and (110) terminations were similar to those in the bulk. [ABSTRACT FROM AUTHOR]

Spin-1/2 orthogonal-dimer chain composed of regularly alternating Ising and Heisenberg dimers is exactly solved in a presence of the magnetic field by the transfer-matrix method. It is shown that the ground-state phase diagram involves in total six different phases. Besides the ferromagnetic phase with fully polarized spins one encounters the singlet antiferromagnetic and modulated antiferromagnetic phases manifested in zero-temperature magnetization curves as zero magnetization plateau, the frustrated ferrimagnetic and singlet ferrimagnetic phases causing existence of an intermediate one-half magnetization plateau, and finally, the intriguing modulated ferrimagnetic phase with a translationally broken symmetry leading to an unconventional one-quarter magnetization plateau. The quantum character of individual ground states is quantified via the concurrence, which measures a strength of the bipartite entanglement within the pure and mixed states of the Heisenberg dimers at zero as well as nonzero temperatures. The parameter region, where the bipartite entanglement may be in contrast to general expectations reinforced upon increasing of temperature and/or magnetic field, is elucidated. [ABSTRACT FROM AUTHOR]

The nonequilibrium magnetic properties (phase transition temperatures, phase diagrams, hysteresis loop areas and correlations) are investigated in the kinetic mixed spin (1/2, 1) Ising nanowire system under the time varying magnetic field. The Glauber-type stochastic dynamics are employed to construct the set of mean field dynamic equations. The time variation of the core/shell magnetizations and the thermal behavior of the dynamic core/shell magnetizations are examined, extensively. The dynamic core/shell magnetizations, hysteresis loop areas and correlations are studied as a function of temperature in order to characterize the nature (continuous or discontinuous) of the phase transitions as well as to find the dynamic phase transition temperatures. The dynamic phase diagrams are presented in the magnetic field amplitude and temperature plane. The dynamic phase diagrams exhibit paramagnetic (p), ferrimagnetic (i), nonmagnetic (nm) phases, three mixed regions, (i + nm), (i + p) and (nm + p). The dynamic phase diagrams contain a dynamic tricritical point and reentrant phenomena, which strongly depend on interaction parameters. • Nonequilibrium magnetic properties of Ising nanowire are investigated. • The Glauber-type stochastic dynamics are employed to construct the set of mean field dynamic equations. • The dynamic phase diagrams are presented in the magnetic field amplitude and temperature plane. • The dynamic phase diagrams contain a dynamic tricritical point and reentrant phenomena. [ABSTRACT FROM AUTHOR]

Magnetic and thermodynamic characteristics of Ising ferrimagnetic core-shell graphene nanoribbon with core spin −2 and shell spin 5/2 were investigated by using the effective field theory with correlations. Some characteristic phenomena have been found in the system. Different saturation magnetization and P-type and Q-type curves were found on the magnetization curves. At low temperature, the magnetization has obvious magnetization platform. Due to the results of exchange coupling, anisotropy and external magnetic field competition, the m 5 -m 7 sublattice magnetization platform presents a concave shape. The results obtained may have potential applications in the design of nanodevices. • Ising model of core-shell structure graphene nanoribbon is suggested. • Magnetic properties of the system have been studied. • Spin-flip or spin-flop has been found on the magnetization curves. [ABSTRACT FROM AUTHOR]