Room temperature ferromagnetism and optical limiting in V₂O ₅ nanoflowers synthesized by a novel method

We report on the observation of room temperature ferromagnetism as well as optical limiting in V₂O₅ nanoflower structures synthesized by a simple and novel cost-effective low-temperature method. The flowers are characterized thoroughly by various analytical techniques to ascertain their structure and composition and to confirm the absence of any impurities. The samples exhibit ferromagnetic properties at 300, 200, and 100 K observed from a hysteresis loop. Coercivity for room temperature synthesized V₂O ₅ flowers is 566 Oe at 300 K and is enhanced at 200 and 100 K. We propose a growth mechanism of the flowers and attribute the origin of ferromagnetism to the introduction of oxygen vacancies in accordance with theoretical predictions available on other oxide nanomaterials. The samples also show optical limiting behavior arising from an effective three photon absorption mechanism as demonstrated by a Z-scan experiment for characterization of optical nonlinearity.