We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering.
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机译:我们目前对超顺磁阻断温度以下的纳米粒子中的磁激发进行简短回顾。在这种温度范围内,纳米颗粒中的磁性动力学受均匀激发的支配,这导致了磁化强度和磁场超精细场的线性温度依赖性,这与块状材料中的Bloch T3 / 2定律相反。 Mössbauer光谱法可以方便地研究平均磁化强度的温度依赖性。磁性纳米粒子的均匀激发能可以通过非弹性中子散射来研究。
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