Compared to the low temperature memory effect observed in magnetic nanoparticles (NPs), here we report a room temperature memory effect in a Ferrimagnetic (FiM)-Antiferromagnetic exchange coupled NiFe2O4-NiO nanogranular system, which is experimentally studied by different protocols of dc magnetization relaxation measurements below the blocking temperature TB = 345 K. The interfacial exchange coupling between the FiM NiFe2O4 clusters and the spin-glassy like phase is proposed to provide an additional anisotropic energy, leading to the enhancement of the magnetic memory effect up to room temperature. The observed memory effect is discussed based on the multiple distribution of energy barriers for both the FiM NPs and interfacial magnetic exchange anisotropy.

中文翻译：

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室温下交换耦合NiFe2O4-NiO纳米颗粒体系的磁记忆效应

与在磁性纳米粒子 (NPs) 中观察到的低温记忆效应相比，这里我们报告了亚铁磁 (FiM)-反铁磁交换耦合 NiFe2O4-NiO 纳米颗粒系统中的室温记忆效应，通过不同的直流磁化弛豫协议进行实验研究低于阻塞温度 TB = 345 K 的测量值。 FiM NiFe2O4 簇和自旋玻璃状相之间的界面交换耦合被提议提供额外的各向异性能量，导致磁记忆效应增强到室温。观察到的记忆效应是基于 FiM NPs 和界面磁交换各向异性的能量势垒的多重分布来讨论的。