Effects of iron substitution on the magnetic and structural properties of Nanocrystalline La0.7Sr0.3Mn1-xFexO3 Perovskites

Lanthanum strontium manganite (LSM or LSMO) has manifestation and interesting bulk properties. La0.7Sr0.3MnO3 has a rhombohedral structure, and it goes from ferromagnetic-metal to paramagnetic-metal at the Curie transition temperature (TC) of about TC=350 K. When magnetic material is subjected to an applied magnetic field its entropy changes. Under adiabatic conditions, the lattice and magnetic parts of the total entropy change by the same amount but with opposite sign. During this process there is a temperature change, which is known as the magneto-caloric effect (MCE). Magnetic refrigeration (MR) is based on MCE and has potential as a future cooling technology. Near room temperature (RT) MR is a promising alternative to conventional gas compression refrigeration due to its unique advantages such as high efficiency and minimal environmental impact. While refrigeration involves about 15% of the worldwide energy consumption, it has been estimated that MR has the potential to reduce the energy consumption by 20?30% over the conventional vapor compression technology. The proposed work is on iron substituted Lanthanum strontium manganite perovskites nanocomposites. The magnetic properties of these materials can be tuned from temperatures higher than room temperature to lower temperatures below room temperature by substituting antiferromagnetic Manganese by magnetic Iron. This approach is promising and offers a huge potential for further studies and technological applications such as finding suitable materials that have a large enough magnetic entropy change at moderate magnetic fields near room temperature.