Ideal Ericsson cycle magnetocaloric effect in (La0.9Gd0.1)0.67Sr0.33MnO3 single crystalline nanoparticles
Single crystalline (La0.9Gd0.1)0.67Sr0.33MnO3 nanoparticles with the perovskite structure have been synthesized by the microwave-assisted hydrothermal process, following calcining of the nanoflower precursor at 900 °C for 2 h. Microstructure analysis was conducted by X-ray diffraction, and scanning and transmission electron microscopy (SEM, and TEM), as well as by field emission SEM, and high resolution TEM which confirmed the perovskite structure in the nanoparticles. Systematic magnetic measurements have been conducted on the nanoparticles. It was found that the Curie temperature can be tuned and decreased with Gd doping. It was also interesting to find that the magnetic entropy change (−ΔSM) in the (La0.9Gd0.1)0.67Sr0.33MnO3 nanoparticles extends over a very broad temperature range as a result of the Gd doping. The −ΔSM has the important feature of remaining almost constant in the temperature range above 60 K, suggesting that this type of nano-material is an ideal Ericsson cycle magnetic refrigerant for applications at room temperature.