Your understanding is partially correct. A magnetic dipole is indeed a property possessed by some particles, but it is not true that some particles have it while others don't. Let me explain in more detail.
A magnetic dipole refers to the configuration of a magnetic field created by a pair of equal and opposite magnetic poles, often referred to as the north and south poles. In the context of particles, such as atoms or subatomic particles, the presence of a magnetic dipole moment indicates that the particle possesses a magnetic field and behaves as if it has a pair of magnetic poles.
Many particles, such as electrons, protons, and neutrons, possess an intrinsic property known as "spin." Spin is a quantum mechanical property associated with particles, and it can be thought of as an intrinsic angular momentum. Particles with non-zero spin have an associated magnetic dipole moment.
For example, electrons have a non-zero spin and thus possess a magnetic dipole moment. This magnetic dipole moment arises from the intrinsic angular momentum of the electron. Similarly, other particles with non-zero spin, like protons and neutrons, also possess a magnetic dipole moment.
However, it's important to note that not all particles have non-zero spin or possess a magnetic dipole moment. For instance, particles like photons, which are quanta of light, do not possess spin or magnetic dipole moments. Photons are described by a different type of quantum property known as polarization.
So, to summarize, a magnetic dipole moment is a property associated with particles that have non-zero spin, and it arises from their intrinsic angular momentum. It is not a property possessed by all particles, but it is present in particles like electrons, protons, and neutrons.