Nakatsuka Yuko, Murai Shunsuke, Fujita Koji, Tanaka Katsuhisa
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
J Phys Condens Matter. 2017 Jan 18;29(2):025802. doi: 10.1088/0953-8984/29/2/025802. Epub 2016 Nov 14.
The spin glass behaviour of 50FeO · 50PO (in mol%) glass has been examined under finite magnetic fields. The Sherrington-Kirkpatrick (SK) model, i.e. the mean field theory, is unsuitable for the interpretation of the frequency dependence of the ac magnetic susceptibility observed under an external field of 0.1 T; the critical exponent derived from the SK model is unphysically large. On the other hand, the droplet model explains well the frequency and field dependence of the spin-freezing temperature and the exponent of the thermally activated process is within the range defined by the droplet model. The results indicate that the spin glass phase of the 50FeO · 50PO glass is unstable against magnetic fields.
