Project: MCSSN

30.08.2012
 
Fresh issue

 

Monte-Carlo simulation of two-dimensional compounds with «Shastry-Sutherland Lattice» structure in the frameworks of classical Heisenberg model.

 

Organization of the Executive:

Theoretical department of ILTPE - B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine

Leader:

Slavin V.V. - doctor of Sciences, leading researcher of ILTPE

e-mail: slavin@ilt.kharkov.ua

Performed by:

Slavin V.V. - doctor of Sciences, leading researcher of ILTPE

Belous L.F. - Ph.D., head of grid-technology departament of ILTPE

Krivchikov A.A. - graduate student of ILTPE

Virtual organization of the project: ung.seed

Duration of the project: 2012 — 2014

 

The aim of the project: studying the magnetic properties of two-dimensional compounds with «Shastry-Sutherland Lattice» structure in the frameworks of classical Heisenberg model, phase-diagram construction in the wide area of parameters.

 

State of the problem

Physical properties of two-dimensional compounds with “Shastry–Sutherland Lattice” (SSL) magnetic structure attract great interest during last years. There are many theoretical and experimental, fundamental and applied works dedicated to the given subjects. These systems are interesting due to a number of unusual magnetic properties, which exhibit various kinds of compounds. Besides, these compounds are attractive for development of non-voltage memory (NVRAM) for computer systems.

 

Scientific novelty of the premise and execution

Recently it has been shown experimentally that magnetic compounds with SSL structure demonstrate a lot of unusual magnetic properties. For example the dependence of magnetization on external magnetic field is a succession of plateau. Magnetization values on each plateau are described well by the sequence of rational numbers (1/8, 1/4, 1/3, 1/2) [1-10]. The origin of such unusual behavior hasn’t studied yet. The aim of current investigations is comprehensive studying of the systems using Monte-Carlo simulations in the frameworks of classical Heisenberg model. For this purpose the calculating package (MCSSN) has been developed. This package uses so called «heatbath» algorithm, which allows ones to increase significantly the efficiency of the simulation in low temperature area. As known, the specific features of the magnets manifest itself in full just in low temperature area. This approach is highly universal and, therefore, allows us to investigate magnetization and internal energy for arbitrary values of temperatures, external magnetic field, exchange integrals, single-ion anisotropy and exchange anisotropy. Parallelization of computations is realized by MPI protocol. Besides just of Monte-Carlo simulations, the search algorithm for the configurations with lowest internal energy is realized. The analysis of these configurations is very important for studying the ground state structure. Our previous investigations have shown that even a small exchange easy axis anisotropy leads to plateau creation which magnetization M=1/3 [12] (Fig.1).

 

Expected Results

It is planned to study the influence of the single ion anisotropy on the magnetic properties of these systems. Previous estimates show that existing of single ion anisotropy could lead to creation of several magnetizations plateaus on the dependence of magnetization on external magnetic field. Besides, using 3D visualization program it is planned to study the ground state structure and, as the result, to construct the phase diagram of the system in wide region of parameters. 

 

 

Fig. 1. Dependence of magnetization M from external magnetic field H for systems size of 24×24 and 48×48

 

Publications

  1.      B. S. Shastry and B. Sutherland, Physica B and C108, 1069 (1981).
  2.      M. Moliner, D.C. Cabra, A. Honecker, P. Pujol, and F. Stauffer, Phys. Rev. B79, 144401 (2009).
  3.      S. Miyahara and K. Ueda, Phys. Rev. Lett. 82, 3701 (1999).
  4.      S. Miyahara and K. Ueda, Phys. Rev. B61, 3417 (2000).
  5.      J.Y. Kim, B.K. Cho, and S.H. Han, J. Appl. Phys. 105, 07E116 (2009).
  6.      F. Iga, A. Shigekawa, Y. Hasegawa, S. Michimura, T. Taka Yamamoto, M. Hagiwara, and K. Kindo, J. Magn. Magn. Mater. 310, e443 (2007).
  7.      S. Michimura, A. Shigekawa, F. Iga, M. Sera, T. Takabatake, K. Ohoyama, and Y. Okabe, Physica B596, 378 (2006).
  8.      S. Yoshii, T. Yamamoto, M. Hagiwara, A. Shigekawa, S. Michimura, F. Iga, K. Takabatake, and K. Kindo, J. Phys.:Conf. Series 51, 59 (2006).
  9.      S. Yoshii, T. Yamamoto, M. Hagiwara, T. Takeuchi, A. Shigekawa, S. Michimura, F. Iga, T. Takabatake, and K. Kindo, J.Magn. Magn. Mater. 310, 1282 (2007).
  10.      M.-C. Chang and M.-F. Yang, Phys. Rev. B79, 104411 (2009).
  11.       H. Kageyama, K. Yoshimura, R. Stern, N.V. Mushnikov, K. Onizuka, M. Kato, and K. Kosuge, Phys. Rev. Lett. 82, 3168 (1999).
  12.        V. V. Slavin, A. A. Krivchikov, Fizika Nizkikh Temperatur, v.37, N.12, p.1264 (2011).