Paramagnetism

Definition

Paramagnetism is a form of magnetism that occurs in materials with unpaired electrons, causing them to be attracted to an external magnetic field. This property arises from the alignment of these unpaired electrons' magnetic moments in the presence of a magnetic field, which enhances the material's overall magnetic behavior. Unlike ferromagnetic materials that retain magnetization, paramagnetic substances only exhibit magnetism when exposed to a magnetic field and lose it once the field is removed.

5 Must Know Facts For Your Next Test

1. Paramagnetic materials typically include transition metal ions, such as manganese (Mn) and iron (Fe), where unpaired electrons are present.
2. The degree of paramagnetism in a substance can be quantified using the Curie Law, which states that susceptibility is inversely proportional to temperature.
3. When a paramagnetic material is placed in a magnetic field, it experiences a positive susceptibility, meaning it becomes magnetized in the direction of the field.
4. Unlike ferromagnetic materials that can retain their magnetization, paramagnetic materials lose their magnetization quickly once the external field is removed.
5. Examples of paramagnetic substances include aluminum, platinum, and certain metal complexes used in biochemical applications.

Review Questions

• How does the presence of unpaired electrons contribute to paramagnetism in materials?
  • Unpaired electrons create individual magnetic moments due to their intrinsic spin. When an external magnetic field is applied, these unpaired electrons tend to align their magnetic moments with the direction of the field, causing the material to become magnetized. This alignment results in an overall attraction toward the magnetic field, demonstrating paramagnetism.
• Compare and contrast paramagnetism with diamagnetism and ferromagnetism regarding electron configuration and behavior in a magnetic field.
  • Paramagnetism occurs in materials with unpaired electrons that align with an external magnetic field, resulting in attraction. In contrast, diamagnetism occurs in materials with all paired electrons and results in slight repulsion from a magnetic field. Ferromagnetism features strong attraction due to multiple unpaired electrons aligning in the same direction, allowing for persistent magnetization even after removing the external field. Thus, while paramagnetic and ferromagnetic materials respond positively to magnetic fields, diamagnetic materials exhibit negative susceptibility.
• Evaluate the significance of Curie Law in understanding paramagnetism and how it relates to temperature changes.
  • Curie Law plays a crucial role in quantifying paramagnetism by relating magnetic susceptibility to temperature. It states that as temperature increases, susceptibility decreases due to thermal agitation disrupting electron alignment. This relationship helps explain why paramagnetic behavior diminishes at higher temperatures and is fundamental for applications like MRI technology where temperature control is vital for accurate imaging. Understanding this law allows scientists and engineers to predict how paramagnetic materials will behave under varying thermal conditions.

Related terms

Diamagnetism: Diamagnetism is a weak form of magnetism that occurs in materials with all paired electrons, resulting in a slight repulsion from an external magnetic field.

Ferromagnetism: Ferromagnetism is a strong form of magnetism seen in materials where unpaired electrons align in the same direction, allowing the material to retain its magnetization even after the external magnetic field is removed.

Magnetic Moment: The magnetic moment is a vector quantity that represents the strength and direction of a material's magnetism, dependent on the arrangement of electrons within atoms.