hysteresis for single nanoparticle

[mohamed...@gmail.com]

dear all

is there any one have an idea on how to get an hysteresis loop. i have used this code but for the whole range of the magnetic applied field the magnetization remain 1.

sim:temperature= 0

sim:equilibration-time-steps=10000

sim:maximum-applied-field-strength=5

sim:loop-time-steps=10000

sim:applied-field-strength-increment=0.1

 

#------------------------------------------

# Program and integrator details

#------------------------------------------

sim:program=hysteresis-loop

sim:integrator=llg-heun

 

#------------------------------------------

# data output

#------------------------------------------

output:applied-field-strength

output:magnetisation

output:magnetisation-length

 

screen:applied-field-strength

screen:magnetisation

best regards

Mohamed

[richard....@gmail.com]

For hysteresis loops at zero K you need to add a small angle between the applied field and the easy axis, since the torque SxH is zero when they are perfectly aligned. You can do this using

sim:applied-field-unit-vector=0.00001,0,0.99999

which gives a small torque and shows a hysteresis loop, seen in the z-component of the magnetization. To get close to the analytical solution Hc = 2K/Ms you need quite slow loops, with a field rate ~1Tesla/ns

Richard

[mohamed...@gmail.com]

Dear Richard,

Thank you for reply.

Best regards,

Mohamed