Monte Carlo simulation of magnetic multilayered structures with giant magnetoresistance effects

Abstract

Abstract. Description of giant magnetoresistance effects in magnetic multilayered structures with the use of the anisotropic Heisenberg model for determination of magnetic properties of thin ferromagnetic films forming these structures is given. Monte Carlo simulations of magnetic properties for structures, which are constructed from two ferromagnetic films divided by nonmagnetic film, are carried out. The temperature and magnetic field dependencies are considered for ferromagnetic and antiferromagnetic configurations of these structures. The calculation of the magnetoresistance is carried out for different thicknesses of the ferromagnetic films. It was shown, that the obtained temperature dependence for the magnetoresistance is agreed very well with experimental results, measured for the magnetic multilayered structures similar to structures, which are considered in our investigations.The physics of ultrathin magnetic films with thickness from one and two to several tens of monolayers appears as a direction of intensive research over the past two decades (for a review see [1]). This heightened interest of scientists is caused by quite a number of unique properties of films different from properties of bulk materials, that defines an importance of these objects for the new facilities of fundamental physics of magnetism, surface physics and their practical applications [2,3]. Thus, the ultrathin films of magnetic metals and alloys are used as the building blocks for magnetic multilayer structures. These artificial created magnetic superlattices has become of great interest in wide range of applications based on the phenomena of the giant magnetoresistance (GMR) [4][5][6] and the tunneling magnetoresistance (TMR) [7][8][9].The multilayer structures with GMR effects consist of the ferromagnetic layers separated by nonmagnetic layers. The thickness of these nonmagnetic metal layers are selected in such a way that the long-range and oscillating RKKY exchange interaction between the spins of the ferromagnetic layers is effective antiferromagnetic. Through this interaction, the magnetizations of the adjacent ferromagnetic layers are oriented opposite to each other. When this structure is placed in an external magnetic field, the magnetization of layers begin to orient in parallel, that leads to a significant change in electrical resistance. Devices based on the GMR effect are widely used as read heads of hard disks, memory devices, sensors, etc [2,10,11].Achievements in the development of technology give possibility now to receive a high-quality ultrathin films and multilayer coatings on the basis of the magnetic transition metals Fe, Co, and Ni [1]. Investigation of the nature of magnetism in ultrathin films and multilayer structures has a large fundamental interest because the dimensional dependence of the magnetic characteristics which demostrate the transition from the specific bulk values for films with thickness of several tens monolayers (d ≥ 10 nm) to the two-dimensional values in films with thickness less than...

Modeling of Magnetic Films: A Scientific Perspective

“…The next study by Prudnikov (2016) is related to the simulation of magnetic multilayer structures with the use of Monte Carlo simulations [ 40 ]. This study presented a description of giant magnetoresistance effects in magnetic multilayer structures.…”

“…This study presented a description of giant magnetoresistance effects in magnetic multilayer structures. A tropical Heisenberg model is employed to determine the magnetic properties of the ferromagnetic films that constitute these structures [ 40 ]. Monte Carlo simulations are conducted to investigate the magnetic properties of structures composed of two ferromagnetic films separated by a nonmagnetic film.…”

“…A novel methodology was developed in this study for determining magnetoresistance using the Monte Carlo method. This approach was employed to calculate the temperature dependence of magnetoresistance for both free layer and spin valve structures and the variant thicknesses of the ferromagnetic films [ 40 ].…”