title: Instability of spin glass phase in divalent iron phosphate glass under a magnetic field.
abstract: The spin glass behaviour of 50FeO · 50P2O5(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 · 50P2O5glass is unstable against magnetic fields.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nakatsuka
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Murai
authors.forename: Koji
authors.initials: K
authors.lastname: Fujita
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Tanaka