Polycrystalline samples of Yb1-xPrxCrO3 (0 ≤ x ≤ 1) were synthesized in the whole solubility range by auto-ignition high-temperature synthesis. TEM images revealed a particle size of about 20–25 nm in the solid solution for as-combustion powders. The crystal structure and the chemical state of the cations were characterized by a combination of X-ray diffraction method and X-ray photoelectron spectroscopy. It is found a complete solubility of the Pr ions and a mixed valence state in the Yb-rich composition range (Yb1-xPrxCrO3; 0 < x < 0.5). There, the presence of Yb2+ ions is compensating by the Pr4+ valence states. Besides, the spectroscopy results found a mix of Cr3+ and Cr6+ valence states in the solid solution. Temperature dependence of DC-magnetization measurements showed that the antiferromagnetic transition increases almost linearly from ~ 119 for YbCrO3 to ~ 243 K for PrCrO3. Furthermore, the magnetization reversal observed in the YbCrO3 is progressively weakened with increasing Pr content and disappears for x = 0.30 of Pr substitution. The isothermal magnetization measured below of TN1 and TN2 (2 K) found that the weak ferromagnetism is canceled in the YbCrO3 magnetic ground state. Opposite to this behavior, the end PrCrO3 composition showed a defined magnetic hysteresis loop which infers a weak ferromagnetic component in the magnetic ground state. Besides, the M–H curves showed a negative exchange bias (EB) effect induced by Pr substitution, which is observed above of x = 0.04, and being more intense for x = 0.10 of Pr composition. The vanishing magnetization reversal and exchange bias effect are influenced strongly by the weak ferromagnetic component arising from PrCrO3 sub-lattice in solid solution. The results demonstrate once again, the importance of the interaction between Dzyaloshinsky–Moriya and single-ion anisotropy in the orthochromite family. Also, the results here could stimulate research toward understanding the magnetic ground state whose investigations below TN2 are scares in both compounds.

中文翻译：

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纳米晶Yb1-xPrxCrO3固溶体的反向磁化和交换偏置效应

Yb1-xPrxCrO3 (0 ≤ x ≤ 1) 的多晶样品是通过自燃高温合成在整个溶解度范围内合成的。TEM 图像显示，作为燃烧粉末在固溶体中的粒径约为 20-25 nm。通过X射线衍射法和X射线光电子能谱的组合表征了阳离子的晶体结构和化学状态。发现在富含 Yb 的组成范围 (Yb1-xPrxCrO3; 0 < x < 0.5) 中，Pr 离子完全溶解并且混合价态。在那里，Yb2+ 离子的存在通过 Pr4+ 价态进行补偿。此外，光谱结果发现固溶体中混合了 Cr3+ 和 Cr6+ 价态。DC 磁化测量的温度依赖性表明，反铁磁转变从 YbCrO3 的 ~ 119 到 PrCrO3 的 ~ 243 K 几乎线性增加。此外，在 YbCrO3 中观察到的磁化反转随着 Pr 含量的增加而逐渐减弱，并且在 x = 0.30 的 Pr 取代时消失。低于 TN1 和 TN2 (2 K) 测量的等温磁化强度发现弱铁磁性在 YbCrO3 磁基态中被抵消。与这种行为相反，最终的 PrCrO3 成分显示出明确的磁滞回线，这推断出磁性基态中的弱铁磁成分。此外，M-H 曲线显示出由 Pr 取代引起的负交换偏置 (EB) 效应，这在 x = 0.04 以上观察到，并且对于 Pr 组成的 x = 0.10 更强烈。消失的磁化反转和交换偏置效应受到固溶体中 PrCrO3 亚晶格产生的弱铁磁成分的强烈影响。结果再次证明了 Dzyaloshinsky-Moriya 与正铬铁矿家族中单离子各向异性之间相互作用的重要性。此外，这里的结果可以刺激研究了解磁性基态，其在 TN2 以下的研究在这两种化合物中都令人恐惧。