1. The Magnetic Properties of the Anti-collinear Phase under the Effects of a Uniform External Magnetic Field in a Two Dimensional Square Planar System By
Naim A. Malak
Physics Department
An-Najah National University, Nablus, Palestine
7- 8 / May / 2007
Supervised by
Dr. Abdel-Ruhman M. Abu-Labdeh

2. Outline Aim The Model in General Terms Monte Carlo Method Results
Summary

3. To investigate the magnetic properties of the
Aim
To investigate the magnetic properties of the
Anti-collinear Phase under the effects of a Uniform External Magnetic Field in an Anti-ferromagnetic Dipolar Planar System

4. The Model in General Terms
Where
a set of two dimensional classical vectors of unit magnitude
g : the strength of the dipolar interaction
h : the strength of uniform external magnetic field
parallel to X-axis
J : the strength of the exchange interaction ( J< 0 )

5. Monte Carlo Method
Constructing an infinite plane from replicas of a finite system
Using the Ewald Summation Technique
Using the slandered Metropolis Algorithm

6. Results

9. Spin Configurations at T=0.1,h=0.1 Anti-collinear Phase

10. Spin Configurations Perpendicular to the applied Field ( Dipolar Anti-ferromagnetic Phase )

11. Spin Configurations at low T and high field Ferromagnetic Phase ( T=0
Spin Configurations at low T and high field Ferromagnetic Phase ( T=0.1, h=8.0 )

13. Summary The Phase Diagram Confirms The following results:
* First Order Transition from the Dipolar Anti-ferromagnetic Phase to Ferromagnetic Phase
* Second Order Transition from the Dipolar Anti-ferromagnetic Phase to Paramagnetic Phase
Besides that, Simulation Results exhibit stable (pi/4) spin configurations at very low ( field & temperature

14. Acknowledgments My father
Dr. Abdel-Ruhman M. Abu Labdeh for supervision
My friends; for help