Magnetic nanoparticles are tiny particles, typically less than 100 nanometers in size, that exhibit magnetic properties. They are often made from materials like iron oxide and can be manipulated using external magnetic fields. Due to their small size, they have a high surface area-to-volume ratio, which enhances their reactivity and makes them useful in various applications. These nanoparticles are used in fields such as medicine, where they can target specific cells for drug delivery or imaging. They also play a role in environmental remediation by helping to remove pollutants from water. Their unique properties make them valuable in both research and practical applications.