Torque magnetometry

[jmiasif]

Respected Ubermag team
Torque magnetometry is a technique where an external magnetic field is applied in a direction relative to a magnetic sample, an the torque produced measured.
This technique can be used to obtain information on the characteristics of the magnetism in the sample like anisotropy.
Sir i have gone through this page of ubermag and want find physics behind Tourque and Anisotropy. i also see the refrence which is given in the bootom of this page but can not understand properly. https://ubermag.github.io/documentation/notebooks/mag2exp/Torque_magnetometry.html

import discretisedfield as df
import matplotlib.pyplot as plt
import micromagneticmodel as mm
import numpy as np
import oommfc as oc
import ubermagutil.units as uu

np.random.seed(1)

region = df.Region(p1=(-150e-9, -150e-9, 0), p2=(150e-9, 150e-9, 100e-9))
mesh = df.Mesh(region=region, cell=(5e-9, 5e-9, 5e-9))

Ms = 9.65e5
H_mag = 2.38e6

system = mm.System(name="Box2")

system.energy = (
    mm.Exchange(A=8.78e-13)
    + mm.UniaxialAnisotropy(K=1.18e6, u=(0, 0, 1))
    + mm.Demag()
    + mm.Zeeman(H=(0, 0, 0))
)

# create system with above geometry and initial magnetisation
system.m = df.Field(mesh, nvdim=3, value=(0, 0, 1), norm=Ms)
system.m.z.sel("z").mpl.scalar()
# minimize the energy
md = oc.MinDriver()
md.drive(system)

# Plot relaxed configuration: vectors in z-plane
system.m.sel("z").mpl()
import mag2exp

mag2exp.magnetometry.torque(system.m, system.energy.zeeman.H)
angles = np.linspace(0, 2 * np.pi, 71)

torque_val_x = np.full_like(angles, np.nan)
torque_val_y = np.full_like(angles, np.nan)
torque_val_z = np.full_like(angles, np.nan)
for i, angle in enumerate(angles):
    system.energy.zeeman.H = (0, H_mag * np.sin(angle), H_mag * np.cos(angle))
    md.drive(system, verbose=0)
    torque_val_x[i], torque_val_y[i], torque_val_z[i] = mag2exp.magnetometry.torque(
        system.m, system.energy.zeeman.H
    )
fig, ax = plt.subplots(dpi=100)
ax.hlines(
    system.energy.uniaxialanisotropy.K,
    xmin=np.min(angles),
    xmax=np.max(angles),
    color="r",
)
ax.hlines(
    -system.energy.uniaxialanisotropy.K,
    xmin=np.min(angles),
    xmax=np.max(angles),
    color="r",
)
ax.scatter(angles, torque_val_x)
ax.set_xlabel("Angle (rad.)")
ax.set_ylabel(r"Torque (Nm$^{-2}$)")
ax.set_xlim([0, 2 * np.pi])
plt.show()

i only understand that tourque is changing with angle rotation of Happlied but anisotropy is contant through out the angle becouse in the programm constant value of anisotropy is K=1.18e6, u=(0, 0, 1) in z direction fixed.
so how this will help us to reveal magnetic characterstics like anisotropy.

Sir, it may be seem like stupid question for you but i can not understand please help me out.
I will be very great full to you all.
thank you.