internal_field_f.va

// VerilogA for internal_field_f - LLG

`include "constants.vams"
`include "disciplines.vams"

module internal_field_f(mx,hx);

inout mx,hx;
ground gnd;
electrical mx,hx;

parameter real alpha = 0.005; //damping constant of the material
parameter real gamma = 17.32e10; // Gyro-magnetic ratio rad/(s.T)
parameter real u0 =  1.25663706e-6; //Permitivity of free space
parameter real Ms= 1.313e6 ;//A\m 
parameter real e = 1.602176487e-19  ; //electron charge in coulombs
parameter real thickness = 2n ; //z-axis
parameter real length = 50n ;//x axis
parameter real width = 50n ; //yaxis
parameter real volume = 2n*50n*50n*3.14 ; //volume of Ferromagnet (free-layer)
parameter real  pi = 3.14 ; // pi value
parameter real h = 1.05e-34;// Reduced Plancks constant

parameter real Kb = 1.38064825e-23; // Boltzmann constant

parameter real Nx =0; // Demagnetization factor for the x-axis

parameter real mean =0; // Mean for gaussian noise

integer seed;

real Hdemag,noise,Hk;

analog begin
 	@(initial_step) begin
seed =1;
end
	Hdemag = -Ms*Nx; // Demagnetizing field
	noise = $rdist_normal(seed,mean,sqrt((2*alpha*Kb*300)/(u0*u0*abs(gamma)*volume*Ms*8p)));// Gaussian noise factor (0 for noiseless)
	V(hx,gnd) <+ Hdemag*V(mx,gnd);
	V(hx,gnd) <+ noise;
end
endmodule