Li Shaozhen, Xu Lisha, Fu Chao, Zheng Mengqiu, Tong Wei, Fan Jiyu
School of Electrical and Electronic Engineering, Wuhan Polytechnic University, Wuhan, 430023, Hubei, China.
School of Physics and Institute for Quantum Materials, Hubei Polytechnic University, Huangshi, 435003, China.
Sci Rep. 2024 Jun 5;14(1):12898. doi: 10.1038/s41598-024-63512-y.
Electron paramagnetic resonance (EPR) studies were performed on LaSrMnO (LSMO) nanocrystalline together with the measurement of its magnetization. Various spectrum parameters including line width, effective g-value and double-integrated intensities have been analyzed in detail. We found nonlinear behavior occurred in the inverse susceptibility far above the Curie temperature T indicating short-range ferromagnetic (FM) clusters and Griffiths-like phase behavior in the paramagnetic (PM) phase. Based on the variation of EPR spectra, except for a typical PM resonance peak, an extra resonance signal was observed in the lower field region and developed as temperature decreased from 320 K to 110 K, which gave a direct evidence of the existence of FM cluster in the PM region of LSMO nanocrystalline. We proposed that the appearance of the Griffiths phase was due to the short FM correlation in the PM regime enhanced by surface spin ordering.
对LaSrMnO（LSMO）纳米晶体进行了电子顺磁共振（EPR）研究，并测量了其磁化强度。详细分析了包括线宽、有效g值和双积分强度在内的各种光谱参数。我们发现，在远高于居里温度T的逆磁化率中出现了非线性行为，这表明顺磁（PM）相中存在短程铁磁（FM）团簇和类似格里菲斯相的行为。基于EPR光谱的变化，除了典型的PM共振峰外，在较低场区域还观察到一个额外的共振信号，并且随着温度从320 K降至110 K，该信号逐渐增强，这直接证明了LSMO纳米晶体PM区域中FM团簇的存在。我们认为，格里菲斯相的出现是由于表面自旋有序增强了PM区域中的短程FM相关性。
