English: The RKKY interaction is a long-range interaction between magnetic moments in a metal. This plot shows the energy of the interaction as a function of distance. The energy oscillates with distance, decaying as 1/r^3. The oscillations are caused by the interaction of the magnetic moments with the conduction electrons in the metal. The RKKY interaction is responsible for the magnetic properties of many metals, including ferromagnetism, antiferromagnetism, and spin glass behavior.

```python import numpy as np import matplotlib.pyplot as plt

def rkkY_interaction(r):

 return (r * np.cos(5 * r) + np.sin(5 * r)) / r**4

r = np.linspace(0.1, 10, 1000) E = rkkY_interaction(r)

plt.plot(r, E) plt.xlim(0, 10) plt.ylim(-1, 1) plt.xlabel("Distance (arbitrary units)") plt.ylabel("Energy (arbitrary units)") plt.title("RKKY Interaction") plt.savefig("rkkY_interaction.svg")

```