We report on the measurement of magnetization in melt-textured YBa2Cu307, samples, in the presence of a crossed remnant flux along the c axis, The ab plane magnetization curves become progressively flatter as the magnitude of the remanence increases. The remanence along the G axis decreases as the field in the ab plane increases, and with decreasing remanence the crossed flux magnetization curves merge with the uncrossed one. The c axis remanence is obselved to help in both the entry and exit of the ab plane flux by effectively reducing the pinning barriers. The decrease of the remanence and flux pinning along the ab plane are discussed in terms of rotation and expulsion of flux, and the possibility of flux cutting.

In this research barium carbonate nanoparticle with composition BaCO3 (Witherite) was prepared by using the gel-combustion (sol-gel) method. A precursor sol was obtained from barium nitrate. The molar ratio of citrate/nitrate=1.3 (CA/NO-3 =1.3) was used to prepare very fine powders of barium carbonate. The gels resulting from these sols were transformed into powders by an auto-combustion process at ≤400oC. The powders consisted of orthorhombic BaCO3 and one another additional phase. The barium carbonate nano-particles produced by the gel-combustion method were calcined in three different calcination temperatures T = 450 °C, T = 600 °C and T =750 °C. The pure orthorhombic phase was found at 450oC X-Ray diffraction. The effect of calcination temperature was studied in three various temperatures. The crystallite size XRD was estimated from the broadening of XRD peaks, using Scherrer's formula. Transmission electron microscope (TEM) and X-Ray diffraction (XRD) of the samples were used for characterization of the obtain products. The size of particles were produced by this method are between 1nm to 10nm.

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