Temperature lag with the onset of exchange bias, superparamagnetic blocking, and antiferromagnetic ordering in ultrathin ferromagnet/antiferromagnet thin film

The magnetization of a nanosized magnet, such as an ultrathin film, thermally fluctuates and can become superparamagnetic. In ferromagnetic/antiferromagnetic thin films, superparamagnetism be suppressed in accordance with antiferromagnetic ordering. exchange bias also induced at the interface, it is nontrivial whether superparamagnetic blocking temperature (TB_SPM) match either onset (TB_EB) or Néel (TN). this study, we investigated dependence parameters coercivity, field, magneto-optic Kerr rotation (?K), AC (MAC) to elucidate matching TB_EB, TB_SPM, TN Pt/Co/Au/Cr2O3/Pt film. Based on dependences MAC, TB_SPM was yielded about 283 K. TB_EB TN, which were determined based ?K, 278 282 K, respectively. almost equal but smaller. This lag caused by difference magnetic anisotropy energy required induce suppress superparamagnetism.