We report the magnetic properties of BaFePtAs₂ compound in a wide temperature range of 5-300 K in the field up to 9 Tesla. The first syntheses of this compound were obtained by conventional solid state reaction technique. The compound crystallizes in the ThCr₂Si₂-type structure with the space group of I4/mmm. This compound exhibits a superconducting phase transition at around 20 K in low field magnetization data. We do not observe zero resistance at this temperature, presumably due to some impurities scattering mechanisms. But, the sample has tendency to gradually lose resistance with decreasing temperature starting at around 7 K. Some significant features were observed in the low field magnetization data. The most striking one is the observed giant diamagnetic contribution to the magnetization below 100 K. Magnetic susceptibility measurements reveal that diamagnetism in the sample is closely correlated with the magnetic structure in the demagnetized state. We observe that diamagnetism is significantly enhanced by thermal treatments. The relationship between the magnetic structure and diamagnetism is discussed by considering the existing theories.

High-field magnetization studies offer a typical magnetic behavior of weak ferromagnets in overall temperature range. On other hand, we clearly observe superconducting M versus H loop at T=5 K. All these results point to a typical of the superconducting weak ferromagnet. As a result, we have examined here a possibility of the coexistence of ferromagnetism and superconductivity in this compound considering the other well-known superconducting ferromagnets in the literature.

我们报道了BaFePtAs ₂化合物在5-300 K的宽温度范围内（高达9特斯拉）的磁性。该化合物的第一合成通过常规的固态反应技术获得。该化合物在ThCr ₂ Si _2中结晶型结构，其空间群为I4 / mm。在低场磁化数据中，该化合物在20 K左右显示出超导相变。我们可能未在此温度下观察到零电阻，这可能是由于某些杂质散射机制所致。但是，随着温度的降低，样品从7 K开始逐渐降低电阻的趋势。在低磁场磁化数据中观察到一些明显的特征。最显着的一个是在100 K以下观察到的巨大的反磁性对磁化的贡献。磁化率测量表明，样品中的反磁性与退磁状态下的磁性结构密切相关。我们观察到热处理显着增强了抗磁性。

高场磁化研究提供了在整个温度范围内弱铁磁体的典型磁行为。另一方面，我们清楚地观察到在T = 5 K时超导M与H的环路。所有这些结果都指向典型的超导弱铁磁体。结果，考虑到文献中其他众所周知的超导铁磁体，我们在此研究了该化合物中铁磁和超导并存的可能性。