Burzo Emil, Tetean Romulus
Faculty of Physics, "Babes Bolyai" University, Kogalniceanu 1, 400084 Cluj-Napoca, Romania.
Nanomaterials (Basel). 2022 May 23;12(10):1782. doi: 10.3390/nano12101782.
The magnetic properties of nanocrystalline MFeO ferrites with M=Fe, Co, and Zn were investigated. The data support a core-shell model, where the core is ferrimagnetically ordered, and the shell shows a spin glass type behavior. The reduced magnetizations of spin glass components follow an m = (1 - ) field dependence. The b values are strongly correlated with the intensities of exchange interactions. The field dependences of the magnetoresistances of FeO and ZnFeO nanoparticles pellets, experimentally determined, are well described if instead of the core reduced magnetization, commonly used, that of the shell is taken into account. For similar compositions of the nanoparticles, identical values are obtained both from magnetization isotherms and magnetoresistances studies. The half-metallic behavior of spinel FeO based nanoparticles is discussed comparatively with those of double perovskites.
研究了M = Fe、Co和Zn的纳米晶MFeO铁氧体的磁性。数据支持核壳模型，其中核是亚铁磁有序的，而壳表现出自旋玻璃型行为。自旋玻璃组分的约化磁化强度遵循m = (1 - )的磁场依赖性。b值与交换相互作用的强度密切相关。如果考虑的是壳层的约化磁化强度而非常用的核层约化磁化强度，那么实验测定的FeO和ZnFeO纳米颗粒球团的磁电阻的磁场依赖性就能得到很好的描述。对于纳米颗粒的相似组成，从磁化等温线和磁电阻研究中都能得到相同的 值。将尖晶石FeO基纳米颗粒的半金属行为与双钙钛矿的半金属行为进行了比较讨论。
