Realizing robust magnetoelectric (ME) coupling effect near room temperature is still a long-standing challenge for the application of multiferroic materials in next-generation low-power spintronic and memory devices. Here we report a systematic study on the magnetic, dielectric, and ME coupling properties of Y-type hexaferrite Ba_0.5Sr_1.5Co₂Fe_12–xAl_xO₂₂ (x = 0.0, 0.5, 1.0) single crystals. The Al doping can induce the shifting of the alternating longitudinal conical (ALC)-proper screw (PS) magnetic phase transition temperature from 200 K for x = 0–365 K for x = 1.0. The most interesting feature is that the Ba_0.5Sr_1.5Co₂Fe₁₁AlO₂₂ single crystal displays a direct and converse ME coupling coefficient with ${\alpha }_H$${\alpha }_H$ ∼3,100 ps/m and ${\alpha }_E$${\alpha }_E$ ∼3,900 ps/m at 250 K, respectively, due to the Al-doped enhanced stability of ALC phase. Moreover, the exchange bias also verifies the strong coupling of electric and magnetic orders. These results provide a valuable insight on the modulation of ALC structure and the mechanism of ME effect in Y-type hexaferrites.

中文翻译：

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Al 掺杂 Y 型六铁素体单晶中接近室温的电和磁序相互控制


在接近室温的情况下实现稳健的磁电 （ME） 耦合效应仍然是多铁材料在下一代低功耗自旋电子学和存储器件中的应用面临的长期挑战。在这里，我们报告了对 Y 型六铁素体 Ba₀₅Sr₁₅Co₂Fe_12–xAl_xO₂₂ （x = 0.0， 0.5， 1.0） 单晶的磁性、介电性和 ME 耦合特性的系统研究。Al 掺杂可诱导交替纵向锥形 （ALC） 适当螺杆 （PS） 磁相变温度从 x = 0 的 200 K 变为 x = 1.0 的 365 K。最有趣的特点是 Ba₀₅Sr₁₅Co₂Fe₁₁AlO₂₂ 单晶显示出 &#x3B1 的正反 ME 耦合系数${\alpha }_H$ ∼3,100 ps/m 和 ${\alpha }_{}$ E ∼3,900 ps/m（在 250 K）时，由于 Al掺杂增强了 ALC 相的稳定性。此外，交换偏置还验证了电和磁订单的强耦合。这些结果为 Y 型六铁体中 ALC 结构的调控和 ME 效应的机理提供了有价值的见解。