All N, Chipara M, Balascuta S, Skomski R, Sellmyer D J
School of Computing, Engineering and Physical Sciences, University of Central Lancashire, Preston PR1 2HE, UK.
J Nanosci Nanotechnol. 2009 Jul;9(7):4437-41. doi: 10.1166/jnn.2009.m73.
FMR measurements on barium ferrite nanoparticles (with an average length of about 13 nm) dispersed within a block copolymer (styrene-butadiene-styrene) are reported. Resonance spectra have been successfully simulated by a convolution of a Dysonian line and a Lorentzian line. The temperature dependence of FMR spectra in the so called in-the-plane and out-of the-plane configurations is reported. The angular dependence of FMR spectra at room temperature is analyzed in detail and simulated within simple thermodynamic model that takes into account the competition between shape and magnetocrystalline anisotropies. FMR data revealed that the local magnetic field acting on uncoupled electronic spin is dominated by the magnetocrystalline contribution, which eventually includes surface effects. The strong connection between FMR spectra and hysteresis loop is demonstrated.
报道了对分散在嵌段共聚物（苯乙烯-丁二烯-苯乙烯）中的钡铁氧体纳米颗粒（平均长度约为13纳米）进行的铁磁共振（FMR）测量。通过戴森线和洛伦兹线的卷积成功模拟了共振光谱。报道了在所谓的面内和面外配置下FMR光谱的温度依赖性。详细分析了室温下FMR光谱的角度依赖性，并在考虑形状和磁晶各向异性之间竞争的简单热力学模型中进行了模拟。FMR数据表明，作用于未耦合电子自旋的局部磁场主要由磁晶贡献主导，最终包括表面效应。证明了FMR光谱与磁滞回线之间的强关联。
