Vampire学习（二）

这一篇主要参考官网Workshop中Day3（PDF_link）内容，联系制作.ucf文件，以及生成skyrmion结构

input file

Code

#-----------------------------------------
# Unit Cell
#-----------------------------------------
material:file=Co.mat
material:unit-cell-file = "file.ucf"
#-----------------------------------------
# System Dimensions:
#-----------------------------------------
dimensions:system-size-x = 10.0 !nm 
dimensions:system-size-y = 10.0 !nm 
dimensions:system-size-z = 2.715 !A
#-----------------------------------------
# Simlation attributes:
#-----------------------------------------
sim:total-time-steps=3000000
sim:equilibration-temperature=30
sim:equilibration-time-steps=10000
sim:time-steps-increment=1
sim:time-step=1e-16

sim:minimum-temperature=0
sim:maximum-temperature=30.0
sim:applied-field-strength=0.0
sim:cooling-time=100!ps
sim:cooling-function=gaussian

#-----------------------------------------
# Program and integrator details
#-----------------------------------------
sim:program=field-cool
sim:integrator=llg-heun

#-----------------------------------------
# data output
#-----------------------------------------
output:output-rate=10000
output:real-time
output:temperature
output:mean-magnetisation-length
output:magnetisation-length
output:magnetisation
output:mean-susceptibility

config:atoms
config:atoms-output-rate=100000

Co.mat file

Code

#-----------------------------------------
# Number of Materials
#-----------------------------------------
material:num-materials=1
#-----------------------------------------
# Material 1 Cobalt Generic
#-----------------------------------------
material[1]:material-name=Co
material[1]:damping-constant=1.0
material[1]:initial-spin-direction=random
material[1]:atomic-spin-moment=1.72 !muB
material[1]:uniaxial-anisotropy-constant=5e-23

file.ucf file

Code

#Unit cell size:
2.715	2.715	2.715	
#Unit cell vectors:
1	0	0
0	1	0
0	0	1
# Atoms num_atoms, num_materials;id cx cy cz mat cat hcat:
1	
0	0	0	0	0	1	0
# Interactions n exctype;  IID i j dx dy dz Jxx Jxy Jxz Jyx Jyy Jyz Jzx Jzy Jzz:
4	tensorial
0	0	0	1	0	0	1.6e-22	0	-1.60e-22	0	1.6e-22	   0          1.60e-22	  0	        1.6e-22
1	0	0	0	1	0	1.6e-22	0	0	        0	1.6e-22	   -1.60e-22  0	          1.60e-22	1.6e-22
2	0	0	-1	0	0	1.6e-22	0	1.60e-22	0	1.6e-22	   0          -1.60e-22	  0	        1.6e-22
3	0	0	0	-1	0	1.6e-22	0	0	        0	1.6e-22	   1.60e-22   0	          -1.60e-22	1.6e-22

这样一个体系，我的PC i7-3770的CPU跑了大概10min。

Vdc .xyz 结构

Povray画图

调参数提升自己

Povray 标签与animation

Code

vi spins.pov

修改其中的Set_Camera_Sky(<0,0,1>)为 Set_Camera_Sky(<1,0,0>)，然后运行

Code

povray spins

图会从上面的菱形变成正方形（角度不同）。然后制作gif动画：

Code

convert -delay 10 -loop 0 *.png animation.gif

加磁场Field Cooling

Code

sim:applied-field-strength=4.0

这是在Day3 幻灯片开始的地方就建议的磁场（单位Tesla）。

结果：