In this paper nanopowders of HoBa2Cu3O7-ä have been prepared by a citrate gel modification of the sol–gel technique. in order to optimize the prepration conditions. the precursor was put under different thermal treatments. In the first thermal treatment, the precursor was heated under oxygen atmosphere at 860°C for 8h and annealed at 700°C for 2h in flowing of oxygen. In the second and third thermal treatments, the precursor was heated at low temperature about 790°C for 8h under oxygen atmosphere and further progresses which were include heating in vacuum (in the second thermal treatment) and Argon flowing (in the third thermal treatment) and annealed in flowing of oxygen were performed. For determination of phase and the size of particles, all samples were investigated by x-ray powder diffraction (XRD) and Scanning electron microscope (SEM) which confirmed the formation of orthorhombic structure for these nanopowders. Room temperature magnetizations measured using a vibrating sample magnetometer (VSM), showed that this nanoparticles exhibits ferromagnetism behavior at room temperature

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